Vol. XXI, pp. 165-170 July 27, 1908 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



NOTES ON THE BREEDING HABITS OF PHRYNOSOMA 

 CORNUTUM AND OTHER TEXAS LIZARDS. 



BY JOHN K. STRECKER, JR. 



Bavi.ui; University, Waco, Texas. 



Our knowledge concerning the breeding habits of the lizards 

 of the genus Phrynosoma is rather limited. The majority of our 

 herpetologists have either been so situated that they could not 

 study these animals in their natural surroundings or have been 

 satisfied to accept the oft-repeated statement that all horned 

 lizards produce living young. As a natural result, there are 

 many naturalists who are not aware that Phrynosoma as well as 

 Sceloporus, contains both oviparous and viviparous species. In 

 the genus Sceloponts, only one species ( N. viviparus Cope)* is cer- 

 tainly known to produce living young while all of the others are 

 supposed to lay eggs. In Phrynosoma, the case is exactly re- 

 versed and only one species is known to be oviparous. This is 

 the very common Texas horned lizard ^Phrynosoma cornutum 

 Harlan), and after a very careful survey of the literature on the 

 subject, I believe that I am the first writer to call attention to 

 this faet.f 



In the writings of Cope, Boulenger, Lydekker, and others, it 

 is stated that the lizards of the genus Phrynosoma and one species 

 of Sceloporus are the only iguanoids that are known to be vivi- 

 parous. Mr. Raymond L. Ditmars, in his excellent workj speaks 

 of the viviparity of the horned lizards, and states that the young 

 usually number from 6 to 12. On plate 39 he shows a photo 

 of two young examples of Phrynosoma <I. hernandesi only two 

 hours old. 



My friend, Mr. C. M. Barber of the Field Museum of Natural 

 History, recently referred me to Mr. C. C. Adams of the Uni- 



* E. D. Cope, Rept. U. S. Natl. Museum L898, p. 332, 

 + Strecker, Proc. Biol. Soc. Wash. 1908, l>. 72-3. 

 t The Reptile Book, New York, 1907, p. 1 1 1 



26— Proc. Biol. Soc. Wash., Vol. XXI. 1908. (165) 



