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its inner margin, the three first of which gradually become larger from base upwards, and bear each, one invaginate spine, the fourth is slightly produced inferiorly (the rounded tip being finely ciliate down to the produced lower middle), there (at the lower middle) bearing two spines directed downward, and a very fine long flagellum at its tip. The arrangement of the bristles of the last two joints, as well as the general outline of the whole, differ from Diaptomus sanguin
The inner branch of the first of the four pairs of natatory legs has two, the rest three joints (see Fig. 8). Their purpose is aëration of the blood as well as locomotion.
The fifth pair of legs in the female is biFig. 7.— Inferior ramose, both branches arise from a two-jointed or second maxilli- basal piece (coxa and trochanter), the inner ped.
branch is short, straight, slender, not jointed, abruptly terminating in a conical tip surrounded with microscopically small spines around a longer median one; at the side
of the tip and opposing each other are two longer, movable (?) spines. The outer branch arises from the second broad basal joint, and is strong, twojointed, terminating in a single, interiorly (near the tip) fine serrate claw, which has exteriorly two (one longer and one shorter) diverging spines a little above its middle (Fig. 9).
The office performed by the transformed fifth pair of legs in
female individuals is not suffiFig. 8.-Form of second, third and fourth natatory legs. xx, inner branch; ciently known. They may be x, outer branch.
for the protection of the eggsac or for properly placing the same, or perhaps they cooperate with the male in copulation. In some cases they may burst or pierce the spermatophores fastened below the female genital pore.
The fifth pair of legs in the male (Fig. 10) are very dissimilar. They both arise from a quadrate coxal joint; the left leg consists
Fig. 9.—Fifth pair of legs of ihe fe. Fig, 10.-Fifth pair of legs of the male. a, inner, and b, outer branch. male. a, right, and b, lefi leg. of four joints, the first joint is quadrate and about one-third wider than long, slightly enlarging distally. The second joint is somewhat enlarged distally, about twice as large as the preceding joint, and bears a strong, wedge-shaped, blunt and finely serrate spine at the inner, and a shorter, slender one at the outer inferior angle. The third joint is clavate and distally tapering. The fourth joint is composed of an anteriorly notched, narrow basal piece exteriorly terminating with an incurved dactyl. The joint is from base to tip of dactyl, about two and a half times longer than the preceding joint; it terminates interiorly with another dactyl, nearly as long as the other; is finely serrate on both sides and acts in closing as a forceps. The right leg consists of five joints, the basal and the second joints are quadrate, the latter enlarges distally and bears a smaller blunt spine at the inner, and a larger one at the outer angle. The third joint is subquadrate, slightly tapering distally, the fourth joint is clavate, bearing a slender spine at the middle of its outer margin, and the fifth constitutes a slender incurved dactyl as long as the preceding joint, finely rugose on the distal half of its inner margin, and is so jointed as to close back against the inner margin of the fourth joint, which thus acts as a hand. The left leg (in Fig. 10, b, purposely drawn larger) reaches only about to the tip of the third joint of the right leg.
In the family of Calanidæ, in general, the abdominal segments are considerably narrower in the male than in the female, the former consisting of five, the latter of four segments. The first of
the five male abdominal segments is as long as the fifth, and is the broadest, its anterior ventral angle is prominent, the second joint is twice as long as the preceding, the third and fourth gradually shorter. Furca, from base to tip of bristles, longer than the first, second and third segments together.
The first of the four female abdominal segments bears ventrally an opening on a circular elevation in Fig. 11, seen from the side).
the female genital orifice, to which the secretion of a
gluey mass, the product of two large orbicular cement -C glands, situated on the segmentation line between the
fifth and sixth thoracic segments, flows. Mounted spec-
Fig. 13. — Front Side view of it is evident, from the position of view of last thoracic the four abdominal seg.
segment below the egg-sac that the products of
which, on the abdo. ments of the the cement' gland and ovary have inen, is seen an eggdominal pore one and the same exit. A receptacu- (the latter drawn laror genital ori- lum seminis is wanting.
ger in comparison fice.
with the rest). The second segment is a little shorter than the first, the third is about half as long, the fourth is still shorter and bears the furca (Fig. 13), with orbicular egg-sac. From thirty to forty eggs are contained in a sac.
The spermatophores containing the fertilizing zoosperms are glued by the fifth pair of legs of the male to the female genital orifice during copulation. I noticed from one to four spermatophores on some females (Fig. 12).
The inaugural dissertation of Dr. Aug. Gruber, “Ueber zwei Süsswasser-Calaniden,” Leipzig, 1878, pp. 34, two plates, gives us the latest knowledge concerning the formation and action of the spermatophores, and as this special work may not be in the hands of every American carcinologist, and owing to the complexity of the matter itself, an abstract of the same, I trust, will be welcome.
In the male the vas deferens can be distinguished into three dis
tinct sections, each of them performing a different
gate (in Diaptomus) zoosperms en-
Fig. 14.--A male abdominal dilated anteriorly, rounded and ta- Diaptomus sanguinesegment with
us var.,enlarged about two spermaio. pering posteriorly. Here we find a
8 times. Side view. phores, c, one central, voluminously swelled mass, is parily and the other en the above mentioned homogeneous glue-mass, periphtirely empty. erically surrounded with a layer of densely packed zoosperms, which but loosely fit into innumerable roundish lodges or hives, the latter constituting the interior of the partly perfected exterior spermatophore capsule. The formation of the latter began probably already in the first section, since the two sections do not functionally differ from each other. This still imperfect spermatophore enters immediately into the third and last section of the vas deferens as soon as the last perfect one has just left the male genital orifice.
A number of zoosperms in the posterior rounded terminus of the spermatophore act as abortive or expelling factors, becoming first granulated toward the perfection of the spermatophore, and, through the endosmotic absorption of water, several of them coalesce with a number of cellular vesicles like soap-bubbles (polygonal in Diaptomus). The expelling cells gradually swell, pressing the central glue-mass into the middle of the spermatophore, and first become nucleate and then plain. Through the further increase of these expelling cells, the central glue-mass is more and more compressed and slowly moves toward and out of the narrow terminus of the spermatophore, and in oozing out forms a saussagelike body, by means of which, in copulation, the spermatophore is glued beneath the valvule of the female genital orifice. Into the center of this mass follows the remainder of the zoosperms, the latter being perfectly surrounded by the former, forming a
minute ball. The glue-mass, according to Dr. Gruber, evidently yields also the material for the formation of the egg-sac, since, firstly, in oozing out of the valvule the eggs are driven into the mass, and secondly, the egg-sac is not formed before the act of sexual union.
SCOLOPENDRELLA AND ITS POSITION IN NATURE.
BY A. S. PACKARD, JR.
able paper," have called fresh attention to this interesting creature, and his discovery of two species in addition to the one originally noticed by the writer, shows that the United States are as much favored as Europe in specific forms. Scolopendrella is a small, whitish tracheate animal, not exceeding a quarter of an inch in length, with a superficial resemblance to a myriopod, such as Scolopendra, having a pair of well developed, five-jointed legs to each abdominal as well as thoracic segment; its name ending in a diminutive gives evidence of the original opinion of its discoverer, that it was a small myriopod, like Scolopendra, the centipede. In deference to the general opinion of naturalists in our “Guide to the Study of Insects,” and our “ Zoology” we have let it remain among the Myriopods, but it occupied an uncertain place, as we waited for more light upon the subject of its affinities, and for time to study it with more care.
Attention was first called to the existence of this type of Tracheates in the New World by a brief notice which appeared in the Proceedings of the Boston Society of Natural History, Vol. XVI, P. III, 1873, which read as follows:
“For nearly two years we have had in the Museum of the Peabody Academy of Science a specimen of Scolopendrella, detected September 8, by Mr. C. A. Walker, under a board in the grounds of the museum. It is nearly related to Scolopendrella immaculata Newport, and if new may be called S. americana. Of the remarkable features in the structure of this animal I do not now propose to speak. It has, however, in the head and antennæ a strong re
1 The structure, affinities and species of Scolopendrella, Proc. Acad. Nat. Sc. Phil., 1881, p. 79.