366 INEZ WIlII'l'LE WILDER AND ELIZABETH BARRETT PEABODY. 



dency toward juvenile hermaphroditism bridges the gap between 

 lower vertebrates where functional hermaphroditism occurs in 

 certain classes and higher vertebrates where the condition occurs 

 only as an anomaly. Swingle has done much to dispel the idea of 

 juvenile hermaphroditism in the anurans. Cases of hermaphro- 

 ditism such as we have here described in Eurycca bislineata give 

 every evidence of being a permanent rather than juvenile condi- 

 tion. On the other hand, although we have thus far found no 

 evidence that these permanent hermaphrodites arise out of an 

 earlier condition in which the gonads have the potentiality for 

 both sexes and may thus be regarded as capable of producing 

 either males, females, or hermaphrodites, we do not feel that our 

 investigation of these early stages has been sufficiently extensive 

 to warrant us in excluding this possibility. In the absence of evi- 

 dence of a chromosomal control of sex determination in this 

 species, and indeed in Amphibia in general, one should maintain 

 an open mind toward other possibilities. Much further investiga- 

 tion of the subject is therefore obviously needed and is now in 

 progress. 



SUMMARY. 



1. True hermaphroditism occurs in approximately constant 

 proportions in every developmental stage of Eurycca bislineata 

 from typical larval to adult. 



2. The percentage of occurrence of. hermaphrodites in this 

 species, based upon the examination of 1,113 individuals, is 1.35 

 per cent. 



3. There are now on record 18 cases of hermaphroditism in 

 urodeles. The first is that of La Valette St. George ('95) in 

 Triton tceniatus, the second is that discovered by Chapin ('15) in 

 Eurycca bislineata, the third is that of Kfizenecky ('17) in Triton 

 cristatns, and the other 15 cases, in Eurycca bislineata, are pre- 

 sented in this paper. 



DEPARTMENT OF ZOOLOGY, SMITH COLLEGE, 

 NORTHAMPTON, MASS. 

 November 13, 1923. 



BIBLIOGRAPHY. 



Bouin, M., 



'01 Histogenese de la Gland Genitale Femelle chez Rana temporaria (L.)- 



Archives de Biologic, Vol. 17. 



