HISTORICAL INTRODUCTION xxiii 



nothing more than a higher development of the ovary. The sperma- 

 tozoa are not recognized as such, and therefore a comparison of egg 

 and sperm is not attempted. He is puzzled to discover how the 

 semen passed from the testis to the vas deferens, and had to abandon 

 this question unsolved. He describes and figures a 'gland' associated 

 with the cloaca of the female Salamander which we now know to be 

 the receptaculum seminis. Rathke's paper therefore contains the 

 first undoubted description of this structure. He does not mention 

 that it contains spermatozoa, but neither does he concern himself 

 with the spermatozoa in the testis. The receptaculum seminis of the 

 Salamander, as already stated, was rediscovered by Leydig in 1853, 

 who found (later) that it contained spermatozoa, but it was not 

 adequately investigated until Siebold ascertained its true nature in 

 1858. Siebold regarded it as a unique structure only occurring in 

 the Salamanders. He overlooked the possibility that the organ might 

 be represented in the male by the pelvic gland, as was suggested later 

 by Blanchard (i 88 i). If the receptaculum seminis is not comparable 

 with the pelvic gland, the cloacal glands of the male have no counter- 

 part in the female. Rathke was the first author to study carefully the 

 male cloacal glands, and he gives good descriptions of both the pelvic 

 gland {Beckendruse) and the anal or cloacal gland {Afterdriise). His 

 views on the nature and functions of these glands have naturally 

 required revision, and the whole situation was reviewed by Blanchard 

 in 1 88 I. Rathke's work is well illustrated, the figures covering the 

 anatomy of the Salamander generally. They are most defective in 

 respect of the urogenital system of the male, the elucidation of which 

 was perhaps beyond the knowledge of his generation. In a later work 

 (1829) Rathke describes for the first time the fragmented adrenal of 

 the Salamander. 



In 1 8 19 Schreibers publishes a very good description, as far as 

 external characters are concerned, of the life-cycle of both species of 

 Salamandra. In atra he never found more than two foetuses in each 

 female. They possessed very large red gills in the earlier stages, 

 which were almost completely lost before birth. In a later paper 

 (i 833) he draws a sharp distinction between the two species in struc- 

 ture, occurrence, and habits. Maculosa produces periodically in 

 water batches of forty to sixty young, the average number being 

 forty-six to forty-eight. In captivity they w.ere born within two con- 

 secutive days, and all were at the same stage of development and of 

 about the same size, and provided with external gills. On the other 

 hand atra never gives birth to more than two at a time. Nevertheless 

 the ovary is relatively as large as in the other species, and as many 



