858 



THE CEUSTACEA. 



§ 29?.. 



consist oF two spheroidal bodies which open externally, by two deferent 

 canals, in front of the tail/''* The copulatory organs are attached to the 

 anterior feet, and consist of hooks and long bristles, by which these animals 

 adhere to the under surface of the thorax of the females/^"* With the 

 13ranchiopoda, the male genital organs have a very remarkable organiza- 

 tion. The testicles consist of two long, straight, caecal tubes, stretching the 

 whole length of the tail. From the upper and dilated extremity of each 

 passes ofi", inwards and backwards, an excretory canal. These canals, 

 shortly after their origin, dilate into a seminal vesicle, and then pursue 

 their course between two longitudinal ridges which run backwards from the 

 base of the tail. At the posterior extremity of these ridges, they open near 

 a process covered with short spines. For the seizure and retention of the 

 females for copulation, the two anterior cheliform feet are provided with 

 antler-like hooks, and, also, at their base, with two peculiar, sometimes digiti- 

 form processes, curved above the front. ^'^> 



With the Poecilopoda, the testicles cl t of ramified canals situated in 

 the cephalothorax, which terminate at that same point on the first pair of 

 post-abdominal feet where are situp the genital openings with the 

 females, in two short, perforated, penis-like organs.'^-* 



With the Laemodipoda, Isopoda, and Amphipoda, the testicles consist 

 of two caeca situated by the side of the digestive canal, and continuous, 

 posteriorly, into two more or less flexuous deferent canals upon the sides of 



Zaddach thinks he has observed with a small num- 

 ber of individuals which had been preserved in alco- 

 )>ol a long time, are only ovaries, the characteristics 

 of which have been effaced by the spirit. As to 

 Cypris, all we know about their males is that their 

 spermatic particles, according to IVagner (loc. cit.), 

 are disproportionately large, and thaX Ledermuller 

 (Microscop. Gemuths-und Augen-Ergötzung, p. 

 141, Taf. LXXIII. fig. d.) thinks he has seen them 

 in cojjulation. Baird, also (Magaz. of Zool. and 

 Bot. I. p. 5'22), has often seen two individuals of 

 Cypris together, but was not sure that they were 

 copulating.* 



W Lov^n, in Wiegmann's Arch. p. 160, Taf. V. 

 fig. l.*! (Evadne). 



10 With the males of Daphnia, there is a hook 

 together with a small long lash on the two anterior 

 pairs of feet situated close under the head. The 

 first pair of feet situated on the beak in front of the 

 mouth, is very long and provided with two small 

 pointed hooks ; while, with the females, these feet 



have the form of two short, obtuse antennae 

 (Müller, Entomostr. p. 87, Tab. XII. fig. 6 ; 

 Ramdohr, loc. cit. p. 25, Taf. VII. ; Straus, Mem. 

 du Mus. V. p. 419, PI. XXIX. fig. 18, 19 ; and 

 Jurine, Hist. d. Monocles, p. 105, PI. XI. fig. 5- 

 8). With the males of Evadne, only the feet of the 

 first abdominal pair are provided each with a hook 

 and some pretty long bristles on their last two arti- 

 cles {Loven, loc. cit. p. 157, Taf. V. fig. 11). With 

 Isaura, on the other hand, the first two pairs of 

 abdominal feet are armed at their extremity with 

 stout nails (Straus, Mus. Seuckenb. II. p. 123, 

 Taf. VII. fig. 4, 13 i aud^o/f/, loc. cit. p. '298, PI. 

 Vft. fig. 2, 6). 



11 Schaejf'er, Der flschförm. Kiefenf. fig. 3-11 ; ami 

 Müller, Zool. danic. Tab. XLVIII. (Branchipus). 

 The frontal digitiform processes are especially de- 

 veloped with Chirocephalus ; see Prevost, in 

 Jurine's Hist. d. Monocl. p. 202, PI. X.XII.t 



12 Van der Hoeven, loc. cit. p. 20, PI. II. fig. 

 14, 18 (Limulus). 



* [ 5 293, note 8.] For the genital organs of 

 Cypris, see Zenker (Muller^s Arch. 1850, p. 191). 

 They closely resemble those of Cyclops. He has 

 also described the spermatophores (Taf. V. fig. 6) ; 

 they are probably the very large spermatic parti- 

 cles seen by IVasrner as mentioned above. These 

 observations I have recently confirmed. fVuf^ner 

 and Leuckart (Cyclop. Anat. and Physiol. Art. 

 Semen, p. 496, note) must, therefore, be mistaken, 

 when they assert the hermaphroditic nature of 

 Cypris, and say, " We beg to direct the attention 

 to the sinmltaneous appearance of egg together 

 with the spermatozoa in the same individual ; and 

 therefore to the hermaphrcKlitic condition of the 

 genitals in Cypris^ It is ])robable that thoy ob- 

 served only females, a.'.d if what they called such 



were really spermatic particles, the time of obser- 

 vation must have been soon after copulation. — 

 £d. 



t [ § 293, note 11.] For the details of the male 

 genital organs of Artemia and Branchipus, see 

 Leydig (loc. cit. Siebold and Kolliker's Zeitsch. 

 III. p. 297). With these Phyllopods, these organs 

 consist of testes, vasa deferentia, and penises ; all 

 of which are double and symmetrical. The testes 

 consist, each, of an oblong poitch which is directly 

 continuous into its vas deferens ; and this last 

 passes into its penis. The two penises are situated 

 at the base of the abdomen, and point, bung-shaped, 

 backwards. Besides these parts, there is an exter- 

 nal organ, style-like, used in copulation (loc. cit. 

 Taf. VIII. fig. 4, a.). — Ed. 



