SEMINATION OF ELEMATOCRYA. 



591 



406 



a spermatozoon is developed, which escapes by solution of the 

 spermatoal wall into the sperm-cell, as in fig. 405. l At this stage 

 the body does not show the spiral disposition. 

 If the sperm-cell has contained numerous 

 spermatoa, the resulting spermatozoa group 

 themselves into a bundle, as in fig. 406 : their 

 bodies are contiguous and acquire the spiral form 

 before escaping from the dilated sperm-cell. 



The spermatozoa are developed in most 

 Batrachia as they are in the Plagiostomi ; a 

 sperm-cell may contain from ten to twenty 

 spermatoa, in each of which the spermatozoon 

 is developed, as in fig. 407, and through solu- 

 tion of the spermatoal membrane the sperma- 

 tozoa become free in the cavity of the sperm- 

 cell, where they usually aggregate into a bundle, pressing the sperm- 

 cell into a pear-shape, which bursts at its small end, and liberates 

 either the filamentary appendages, as in the Frog, or the spiral 

 bodies, as inPelobates : in either case the remains of the 

 sperm-cell continue recognisable, for some time, at the 

 non-liberated ends of the spermatozoa, as in fig. 408, a. 



In the igneous Toad {Bombinator igneus) the 

 spermatozoa lie confusedly within the sperm-cell : 

 the remains of the spermatoon long adhere, like a 

 pectinate appendage, to the spermatozoon. When 

 fully developed and liberated, the spermatozoa show 

 a long cylindrical body, attenuated towards the head, 

 Avhich is again slightly enlarged, and more gradually shrinking 



Bundle of Spermatozoa 



within the sperm-cell. 



TorprdoNarce. cccvi. 



407 



Spermatoon 

 with its con- 

 tained sperma- 

 tozoon, from 

 the sperm-cell 

 of a Frog, 

 cccvu. 



408 



409 



410 



Bundle of Spermatozoa, c, 

 escaping from the sperm- 

 cell, a. Pelobates. ccovi. 



Spermatozoa of Bombinator 

 igneus. 



Part of Spermatozoon of 

 Triton. 



into the filamentary tail, which is reflected and coiled in narrow 



i << < 



'Sometimes the entire nucleus becomes a coil of fibre." — Barry, cvn. 1842, pis. 

 v. VI. XI. 



