The male Linguatala is, as in dicecious Entozoa generally, much smaller than the female: the generative apparatus consists of two winding seminal tubes or testes, and a single vas deferens, which carries the semen from the testes by a very narrow tube, and afterwards grows wider. It communicates anteriorly with two capillary processes, or penes, which are connected together at their origin by a cordiform glandular body, repre senting a prostate or vesicula seminalis. The external orifices of the male apparatus, accord ing to Minim, are two in number, and are situated on the dorsal aspect of the body, just behind the head.
Diesing, however, describes the male Pen tastant as leaving only a single penis, which perforates the interspace between the second and first segments of the body, and protrudes below and behind the oral aperture.
Much interest attends the consideration of the reproductive organs of the dicemous En tozoa, since they are the first and most simple forms of the animal kingdom which present that condition of the generative function. In the Acanthoeephala the structure of the generative apparatus has been ably elucidated by Cloquet in the species which commonly infests the Ilog, viz. the Echinorhynchus gigas. The male organs consist of jr:' testes, two vasa defe rentia, which unite together to terminate in a single vesicula seminalis, and a long penis gifted with a particular muscular apparatus.
The testes (f; h, fig. 93) are cylindrical bodies, pointed at both ex tremities, of nearly the same magnitude, but situated one a little anterior to the other. The anterior one is attached by a filamentary process (g) to the posterior extrcrnity of the proboscis : the posterior gland is connected by a similar filament to the in ternal parietes of the body. The vasa diferenlia (i), after their union, form sem , ral irregular dilatations (k), which together constitute a lobulated vesicilla seminalis. This reservoir is filled with a white grumous fluid like that which is found in the testes, and it is embraced posteriorly by the retractor muscles of the penis (r, r), which form a kind of coni cal sheath for it.
A small, firm,white, and apparently glandular body (q) is situated at the point of union between the vesi cula seminalis and the penis.
The penis is a straight, cylindriatl, firm, white or gan, and in the retracted state is terminated by a di lated portion (o), occupying the posterior extremity of the body, but which disap pears when the intrornittent organ is protruded. This
action is produced by the muscles s, s, when the penis presents the form of a short broad cone, adhering by the apex to the caudal extremity of the body : it is retracted by the muscles r, r, above described.
The female organs consist of two ovaries and one oviduct. The former are long and wide cylindrical canals, which of themselves occupy almost the whole cavity of the body extending from the proboscis to the tail (h, h, fig. 83). They are situated, one at the ventral. the other at the dorsal aspects of the body, and arc separated in the greater part of their extent by a septum : see fig. 84, j; g, which shows them in transverse section. They contain a prodigious quantity of ova, and adhere by their outer surfaces very firmly to the muscular parietes of the body.
The dorsal ovary opens into the ventral one by an oblique valvular aperture about an inch distant from the extremity of the proboscis, anterior to which the common cavity extends forwards between the lateral lemnisci, and terminates by a conical canal (i, fig. 83), which is attached to the posterior portion of the pro boscis. The two ovaries terminate in a dif ferent manner posteriorly, the dorsal one end ing in a cul-de-sac, the ventral becoming continued in a slender oviduct (k), which opens by an extremely minute pore at the caudal extremity of the body (I). The tissue of the ovaries is remarkable for its trans parency and apparent delicacy, but it pos sesses a moderate degree of resistance.
The generative organs in the Nematoidea are upon the whole more simple than in the Acanthocephala.
The testis in each of the genera is a single tube, but differs in its mode and place of ter mination, and the modifications of the intro mittent part of the male apparatus have afforded good generic characters.
Genitale masculum, spiculum simplex, is the phrase employed by Rudolphi in the formula of the genus Filaria, and this appears to be founded on an observation made on the Filaria papillose, in which he once saw a slender spicu him projecting from near the apex of the tail. According to the recent observations of Dr. Leblond,s the male-duct in the Eilaria papil lose terminates at the anterior extremity of the body close to the mouth. From this aperture the slender duct, after a slight con tortion, is continued straight down the body to a dilated elongated sac, which represents the testis.