SEXUAL CHARACTERS—ELASMOBRANCH FISHES 265 
LITERATURE 
The chief standard works on the claspers of the elasmobranchs are: 
JunGERSEN, H. F. E. 1898 a Ueber die Bauchflossenanhinge (Copulationsor- 
gane) der Selachierminnchen. Anat. Anz., Bd. 14. 
1898 b Om appendices genitales hos havkalen, Somniosus micro- 
cephalus Bl. Schn., og andre Selachier. Danske Ingolf-Eped., vol. 2, 
no. 2. 
Huser, O. 1901 Die Kopulationsglieder der Selachier. Zeitsch. wiss. Zool., 
Bd. 70. 
Jungersen deals almost solely with the musculature and the skeleton of the claspers, in 
some species with the skeleton exclusively. The siphon (referred to here as the ‘glandular 
sac’) is only mentioned in passing, except in the case of Rhina squatina, where it is figured 
partly dissected in situ. No histological details are given. 
Huber’s paper is on the same lines as Jungersen’s, but the external features of some of the 
claspers are figured. The species, however, differ {from those dealt with in the present 
paper. 
Bouau, C. C. H. 1881 Ueber die Paarung und Fortpflanzung der Scyllium 
Arten. Zeitsch. wiss. Zool., Bd. 35. 
This is the first paper giving an account of an observation of the copulation of an elasmo- 
branch in an aquarium. It states that only one clasper was inserted at a time and that 
the coition lasted twenty minutes. 
Acassiz, Louis 1858 (On the reproduction of Selachians.) Proc. Boston 
Socy. Nat. Hist., vol. 6, p. 377. 
Agassiz first formulated the idea, later widely copied, that the siphon is a reservoir for 
spermatozoa. This opinion was based upon no evidence. 
ScHnemwER, Anton F. 1883 Ueber die Begattung der Knorpelfische. Zool. 
Beitrige, Bd. 1. 
Schneider was the first to state that he had found spermatozoa (quantity not noted) in 
the siphons of Acanthias and Callorhynchus. No proof was given. He does not appear 
to have made a microscopical examination to determine what he saw was spermatozoa 
or was merely a mucous secretion of the walls of the siphon. 
RepEKE, Hetnricu Cart 1898 Het urogenitalsystem der Selachier en Holo- 
cephalen. Akad. Proefschrift, Helder. 
Redeke states that in Mustelus, postmortem, he found the siphon half full of sperma- 
tozoa. There is no suggestion as to how they entered. In my laboratory experi- 
ments on Scyllium catulus, described above, an explanation is given of how this may have 
happened. 
