1076 



SCANDINAVIAN F I SI IKS. 



kidney (the W'olftiaii hoth) is sciiMi-jitefl in tiie luaics 

 from the ])osterioi' part, and is applied, as an epidi- 

 djjmls, to tlie aiitei'ioi' jiart of each testis, receiving 

 the efferent duct then-ot'. 



In the structure of the generative organs the Elas- 

 nmhranchs are even more closely approximated than 

 the Chondrosteans to the higher vertebrates. These 

 organs are generally more restricted in extent, whence 

 it naturally results that the offspring is far less nu- 

 merous than that of the Teleosts. The efferent duct 

 (vas deferens, lig. 801, o) of the male organs («) passes, 

 as in the higher vertelira.tes, first tiirough an epididii- 

 mis. Before opening into tlic cloaca, it widens into a 

 dilatation (seminal vesicle, jt), the posterior extremity 

 of which is applied to tiie corresponding part of the 

 seminal vesicle on the other side of the body, and then 

 finds outlet, in common with the other seminal vesicle 



their sliniA' secretion. .\ large gland of this kind i.s 

 .situated on the under side of tlie \entral tins. In most 

 cases the said organs are besides furnished at the tip 

 witii cards of teeth or with s])ines. 



The copulation between the sexes that is practised 

 with the aid of these organs by the Sharks has been 

 observed in the case of the Nurse Hound {Sri/JIinrhinus 

 stell(iris) bv Boi.AU at the Hamburg Aquarium, and is 

 illustrated by the aj^jiended figure (302). Of tlie copu- 

 lation of the Rays Hollbekg writes'': "During the 

 season of propagation they repair to the surface of the 

 sea and, for the ]«irpose of depositing their eggs, to 

 the shores. At these times they are taken with the 

 harpoon. The female is frequently attended by several 

 males, who endeavour by lifting and tossing her with 

 their snouts to turn her over on her back. The first 

 to succeed in this applies and presses his \eiitral side 



ITig. 302. Male Nurse Himiul cltisping- (lie female dnrins eopulatin 



AfdT BuLAU, Zeitsc-hr. f. wiss. Zoo)., Bd. XXXV, p. ,^22. 



and the ureters, into a special cloaca {k, the urogenital 

 cloaca, MoEEAU, Hist. Nat. Foiss. Fr., tome I, fig. 26, 

 p. 246), which projects on the wall of the anal cloaca 

 in the form of a ])apilla (r) only recpiiring the erectile 

 tissue to re])resent a true penis. In the Chimicras the 

 urogenital aperture of the males lies externally on the 

 ventral side, at the anterior extremity of an oblong 

 and compressed, but posteriorly tumid protuberance 

 behind the vent. 



The external copulatory organs of the males we 

 have mentioned above. The most impoi'tant, the .so- 

 called pterygopodia of Petri", consisting of the trans- 

 formed hindmost radialia of the ventral fins {metapte- 

 ri/f/iiiiii in Gegenbaur; fig. 301, I; fig. 295, ptpd), are 

 composed of .several parts and furnished with a longi- 

 tudinal channel, into which several glands discharge 



so closely to hers that, if only one of them be har- 

 pooned, both may be drawn out of the water without 

 being ])arted." On the occasion described by Bolau 

 the right ]jteryg(jpo(lium of the male \vas inserted into 

 the sexual aperture of the female. The male flung his 

 tail upwards and forwards along the right side of hei- 

 body and bent his c)\\ n in the opposite direction, though 

 with the dorsal side under, so that the top of his head 

 pressed his tail to the back of the female above her 

 pectoral fins. In the last-mentioned circumstance we 

 may perhaps find a clue to an explanation of the man- 

 ner in whieli the male Chinuvras emplov' the mobile 

 prehensory organ situated on their forehead. The co- 

 pulation of the Chima3ras has never been obsei-ved; but 

 as the mouths of the two oviducts, which open in the 

 females of these fishes beside each other and externally, 



" Zeilsclir. wiss. Zool., Bd. XXX, p. 291). 



' Gbgs Wett., Witt. Snmli. N. Hamll., lU Dolen (ISIO). p. ItJ. 



