^293. 



THE CRUSTACEA. 



357 



Crustacea completely resemble, as to form and situation, the ovaries and 

 oviducts of the females, except that the deferent canals are dilated, before 

 their termination, into two seminal vesicles.® 



With Argulus, the males have, at the base of their last pair of feet, a 

 hook which is used in copulation. But as to their internal organs, there 

 are, as yet, no credible observations. <^^ 



With the Cyclopidae, the male organs consist of a single pyriform testi- 

 cle, the Vas deferens of which curves, first forwards, then backwards, and 

 opens at the base of the tail on the median line. In the lower end of this 

 canal, a homogeneous, cylindrical envelope is formed around the sperm, — 

 a real spermatophore, which has a narrow neck, and which the males glue 

 to the vulva of the females.'''' For effecting this last, the males have one 

 or even both of their antennae incrassated at their base, and provided with 

 a special article near their extremity, which gives these organs a forficulate 

 character. <®' When the male, by the aid of these antennae, has embraced 

 the abdomen of the female, he bends the posterior part of his body for- 

 wards, and seizes hold of the female a second time with the forficulate foot 

 of the second pair, at the same time grasping, with the other and digiti- 

 form foot, the spermatophore as it is escaping from the genital opening, and 

 attaches it to the vulva. ''^^ 



As yet we possess only quite incomplete observations upon the males 

 of Daphnioi'dae, Cypridoi'dae, and Apodidae, which are found only at cer- 

 tain seasons of the year.'*' With the species yet observed, the testicles 



3 Rathke, Nov. Act. Nat. Cur. XIX. p. 149, Tab. 

 XVn. fig. 17. I do not know how it is with the 

 males of the other Ergasilina, for as yet we know 

 only the females of these animals. 



4 Jurine, who was the first to notice these 

 copulatory organs of the male Argulus, says he 

 perceived at the base of the penultimate pair of feet 

 a vesicular swelling containing, he thinks, a fecun- 

 dating liquid (Ann. du Mus. loc. cit. p. 448, PI. 

 XXVin. fig. 1, 21).* 



5 For the formation of these spermatophores with 

 Cyclopsina castor, and minutus, see my Beitr. 

 zur Naturg. d. wirbellosen Thiere, p. 36, Taf. II. 

 fig. 41-44, or Ann. d. Sc. Nat. XIV. 1840, p. 26, 

 PI. V. B. I have shown how their contents are 

 thrust out in passing the neck by the action of a 

 peculiar substance which swells when in contact 

 with water. 



6 The two antennae are thus endowed, with Cy- 

 clops quadricornis, Cyclopsina minutus, and 

 alpestris ; while this organization obtains with one 

 antenna, only, with Cyclopsina castor, and Ano- 

 malocera Patersonii ; see the figures of Muller, 

 Entomostraca ; and Jurine, Hist. d. Monocles ; 

 also Vogt, Schweiz. Denksch. loc. cit. p. 18, Taf. 

 II.; and Templeton, Trans, of the Entomol. Soc. 

 II. p. 35, PI. V. fig. 1, 5. The asymmetrical pos- 

 terior pair of feet has been figured by Jurine, loc. 

 cit. p. 61, PI. IV. fig. 2, PI. VI. fig. 11 {Cyclop- 



sina castor), and by Templeton, loc. cit. p. 37, 

 PI. V. fig. 1, 18 (Anomalocera). 



7 These spermatophores, the true signification of 

 which was unknown until lately, are found, often 

 in the numbers of four to six, upon the same 

 female, after several coitions occuiTiug at different 

 intervals ; see Muller, loc. cit. Tab. XVI. fig. 5, 

 6, and Jurine, loc. cit. PI. IV. fig. 6 {Cyclopsina 

 castor) ; also Ramdohr, loc. cit. Taf. III. fig. 6, 9, 

 and Jurine, loc. cit. PI. VU. fig. 2, 14 (Cyclop- 

 sina minutus). The spermatophores of this last 

 have the form of a curved horn, and become, after 

 a time, of a brown color. With Cyclops quadri- 

 cornis, the sperm does not appear to contain 

 spermatophores at the moment of its evacuation. 



S The males of Polyphemus, Limnadia, and 

 Apus, have not yet been observed. It is said, it is 

 true, that Kollar (Isis, 1834, p. 680) has discov- 

 ered those of Apus cancriformis ; but as yet 

 nothing definite has been learned about the matter. 

 At all events, the description given by Zaddach 

 (loc. cit. p. 53, Taf. I. fig. 15, 16, and Taf. III. fig. 

 1, P.) of the male genital organs of these Crustacea, 

 is unsatisfactory, for at the point, where, according 

 to this naturalist, are found the two male genital 

 orifices surrounded by short spines, that is, on the 

 dorsal surface of the last segment of the body, are 

 found, with all the females also, similar orifices. It 

 is therefore probable that the ramose testicles which 



* [ § 293, note 4.] For the male genital organs 

 of Argulus, see Leydig (loc. cit. Siebold and 

 K6lliker''s Zeitsch. II. p. 341). The testicles con- 

 sist of two pouch-like organs, situated, one in each 

 caudal fin ; they send off, each, a vas deferens 

 which terminates in a seminal vesicle ; from this 

 last pass off two deferent ducts w^hich end in the 

 common genital orifice. Just before reaching this 

 orifice, each of these ducts is joined by another 



coming from an accessory gland, which is pouch- 

 like, and stretches back of the seminal vesicle. As 

 auxiliary copulatory organs may be regarded a 

 hook situated on the anterior border of each of the 

 last pair of feet, and a nodule or papilla in the 

 posterior border of the penultimate pair, corre- 

 sponding, oppositely, with the hook. These hooka 

 were taken by Jurine for penises, and the papil- 

 lae for seminal capsules. — Ed. 



