was the thickest part, was about one-eighth of the entire length. That it was an individual organism I had not the least suspicion. It was solely its white color, in such direct contrast with the dark adipose tissue, in which it was contained, that excited my curi

Fig. 117.

Anterior portion of Echinorhyn

cus gigas, showing the projected

proboscis, with rings of hooklets.

osity. On this account it occurred to me that the microscope might reveal some difference in structure. Having put it under a lens of very moderate power, I was surprised to see a vermicular object, with the thick end truncated. Now a deep regret seized me; for I supposed that in the dissection of the eel, the most important part of this interesting specimen had been unwittingly cut off. The appearance thus presented in the microscope is shown in Fig. 120, where it looks like a worm with its anterior end excised. Thus regarding the object as ruined by an untoward accident, I was about to cast it aside, when lo! to my glad astonishment, the creature began a singular movement at the supposed decapitated end. Astonishment is not the word-it was in amazement that I gazed upon that strange movement. Such a sight could never be forgotten. Who does not remember the childlike delight at seeing for the first time a juggler draw the almost interminable cornucopia out of his mouth, until the mountebank's head looked like that of the fabled Unicorn? But that was only a smooth paper cone, after all; and the trick of it every schoolboy well understands. Not so with this feat of my puny capitve, at whom I had the lone privilege of gazing through this wonder-peering instrument. Like the sheriff, who was obliged on account of his pleasant bearing, to respect the unwelcome tenant whom he had just ejected; so I must confess that this unpleasant occupant whom I had ousted from its strange dwelling-place, had compelled my admiration, by a singular gracefulness of form and

Longitudinal section of E. gigas, showing proboscis re

tracted, the booklets still exter protractile muscles, ce, the re

nal. a, the oral pore. bb, the

tractile muscles. (From Owen.)

movement, albeit certain outré and weird-like accomplishments. With a slow, steady and uniform movement, a beautiful and tiny structure rises up, until the truncated end is capped or surmounted by a pretty little pagoda, with many circlets of hooks, the distance from ring to ring, being uniform. It was as

if a miniature tower had risen out of a little crater, and covered it with its base. The whole structure is pellucid, like old milkywhite china. So that now the end that seemed to be cut across is completed by having a cone projected on it as a base, the apex terminating almost in a point. At this extremity is a little pore, which probably serves whatever of oral function is needed, hence it may be called its mouth. Fig. 121. The evolving of that pretty cone was not only a beautiful sight to

Transverse section of

E. gigas, aa, Leminisci. the neck by a thin ap

attached to the sides of

pendage, and ending in a

cul-de-sac, supposed to

be nutrient processes. canals bb, cylindrical

which adhere closely by muscular fibre. cc, tri

the other side to the

tral ovary sac, or testis. (From Owen.)

look at; but the method of its evolution was a grand thing to see into. As it rose slowly, sack, or testis. 7. Venit was a lengthening truncated cone, with a crater at the upper, or smaller end. And this cone, although without change at the base, kept steadily lengthening at its sides, and narrowing at the top, until at length the truncation, and the crater disappear together the former in a rounded point, and the latter in a pore. Fig. 122, a, b, c, d.

Fig. 120.

But how could this be done? It should be mentioned that a similar extensile organ in other entozoa has been called by naturalists, from sheer poverty of language, the "proboscis." Hence there is no help for it; and we must use the same inexpressive word. There is a species to which our specimen is allied, which is known by the name Echinorhyncus gigas. Its proboscis, when protruded, is of a spherical form, with a neck, or stem below; while at the top of the sphere is a slight projection, around which are several rows, or rings of hooklets. In the centre of the ring that surrounds the top is the oral pore. Figs. 117 and 118, a. Without regarding form precisely, but rather looking to function, let us liken the neck of the animal to the hand of a glove, and the proboscis to one of its fingers. Suppose that finger to be with

Koleops Anguilla in

repose, the probos

cis withdrawn giv

ing the truncated appearance.

drawn, or inverted. There are two ways in which I can revert the same. I may wish to do so by starting the tip end of the finger, as if I should push it out by pressing the end of a wire upwards, against the under side of the tip, which would in this way come out first or I could, if I wished, push the finger out at the sides. This could be done, for illustration, by having in the hand part of the glove a tube or cylinder of the proper size, down which the glove finger has been neatly pushed, so as to fit snugly against the inner sides of the cylinder. Now if the cylinder be gently pushed upward, the glove finger will ascend on the outside of the cylinder having, as it rises, a crater-like depression at the top. The first of these methods illustrates the propulsion of the pro

Fig. 121.

boscis of Echinorhyncus gigas: and the second one shows the actual evolution of the proboscis of our new entozoon. It is done by the pushing of abductor muscles on the sides of the everting and lengthening cone.

It is noticeable of our species, that when the proboscis is returned into the body, the hooklets are all turned inside the proboscis. Fig. 122, e. This is not true of Echinorhyncus, which keeps its hooklets external to the proboscis, whether that organ is extruded or withdrawn. Figs. 117, 118.

Three real, and easily appreciable distinctions showing the rings or are now pointed out in these two helminths. They differ greatly in the form of the proboscis : also in the method of propulsion of the same, a method requiring for each differently adjusted muscles; and they differ in the position of the hooklets, when the respective probosces are inverted. It is plain then that our specimen belongs to a new genus.

As to their ordinal relations; both are members of Owen's second Class of the Entozoa, embracing the Sterelmintha, or Solid worms; and both evidently belong to Duvaine's Type iv., Acanthocephala, or Spiny Heads; and to Rudolphi's Order iv., which bears the same name. Now in this order there is but one genus. namely, Echinorhyncus, already mentioned; therefore we put in the order a new genus, to which we give the name Koleops, meaning sheathed-head" and species Anguilla, because found in the common eel.

But the systematist may claim a word. If our name is to be accepted, the giving must respect the methods which Science regards as Orthodox. Accordingly the following is offered as sufficiently technical to be precise; and yet perfectly appreciable by the popular judgment.

KOLEOPS ANGUILLA Lockwood (gen. et sp. nov.).

Description.- Solid. Form, vermicular, truncated at anterior end, when at rest; when in action the proboscis extended, making with body two cones united at their bases. Length, less than a line when at rest. Thickness at base about one-eighth of length. Proboscis encircled by rings of hooklets external to the cone and pointing backward; when the proboscis is retracted, the hooks are internal to the cone, and point forward. Color tallowy-white, pellucid. At extremity an oral pore.

Fig. 122.

d

K. Anguilla; a, b, c, d, showing the progressive projection of the of proboscis when withdrawn, proboscis. e, showing position

with the hooklets inside of the

cone.

Habitat. In adipose tissue on the entrails of the common eel, Anguilla acutirostris. Specimen taken from an eel caught in Raritan Bay, near Keyport, N. J. Spring of 1869. As to the use of those spiny circlets on the proboscis. While they can present but very little obstruction to the penetrating of that organ, the hold thus given the little parasite is very great; indeed it is certain that any attempt to dislodge it must fail, while these grapnels are buried in the tissue, and but for the peculiar muscular functions of the cone-like proboscis, its extraction must be fearfully lacerating, like the withdrawing of an arrow with many barbs. Certain it is that no human device could extract that tiara shaft of spiny rings, from the living tissue, without inflicting an agony beyond expression. When the butcher lifts the meat off his shamble hooks, he does it with a motion suited to the form of the hook, that he may not tear the meat. When Koleops would retract its thorny shaft, the process is begun at the extreme point, which of course is at the bottom of the wound; and how deftly, easily, yea, perhaps painlessly, this is done. Involution is begun at that extreme point. The end of the proboscis sinks downward within itself. In fact, it is not a withdrawing in the ordinary sense; for that would make the entire organism move at once, and every barb would tear. It is a gradual involving, beginning at the point, and of course, the first circlet of hooks is by this involving, everted from its hold, and inverted as respects the deepening crater of the now shortening truncated cone. Given the problem, economy of suffering, could a solution more admirable be afforded? It is to be observed that the instant the point of the proboscis reënters the neck on its return into the body, the

part without, or external to the neck, is a frustrum of a cone, while the part now within, or below the neck, is a lengthening cone, until the external frustrum wholly disappears, and the internal cone is complete; and the animal is at rest.

But little beyond conjecture can be said on the mode of use of the oral pore. It may be a sucking organ, thus imbibing nourishment. To me it seems that the entire external walls of the proboscis are functional in this direction; and during the slow inversion of this instrument, that is, while withdrawing from its hold, as each ring of hooklets is released, and involved into the crater of the returning cone, the limpid adipose flows over the crater's edge; thus the cone when returned contains a supply of nutriment. I hardly know how heterodox the view may seem to some, yet the idea presses me that the osmotic doctrine of a chemical impulsion of the nutrient fluids and gases, plays an important role in the nutritive system of these curious beings.

But my pen must stop with a confession. I must own that during the study, whose results have been given above, the so called repulsiveness of the subject was both unseen and unfelt, in the reverent sense that came upon me; so that in studying this singular organism, so lowly and so minute, with a functional structure so complete and complex, with adaptations so skilfully adjusted to a mission so mysterious-I found myself, not without emotion, repeating the sublime words of Saint Augustine: Deus est magnus in magnis, maximus autem in minimis.

NOTE.-An oral account of my discovery, with some blackboard chalking, was given to the N. Y. Lyceum of Natural History, May 12, 1869. November 14, 1871, I read a paper, giving the results of my study, before the New Jersey Microscopical Society. From that paper the principal facts given above have been taken.-S. L.

ON THE USE OF MONOCHROMATIC SUNLIGHT, AS AN AID TO HIGH-POWER DEFINITION,*

BY DR. J. J. WOODWARD, U. S. ARMY.

A FEW years ago I published, in the "Quarterly Journal of Microscopical Science" (Vol. vii, 1867, p. 253), some brief remarks

* Read before the Philosophical Society of Washington, March 9, 1872.