8 BULLETIN 194, UNITED STATES NATIONAL MUSEUM 



Siredon humboldtn DumiIkil, Bibron, and Dum^ril, Erp6tologie g6n6rale, vol. 



9, 1854, pp. 177-181 (lake near Mexico City; types probably in Mu3. Hist. 



Nat. Paris). 

 Gyrinus edulis Dum^ril, Bibron, and DtrinfiRiL, Erp6tologie g6n6rale, vol. 9, 



1854, p. 178 (types and type locality same as preceding). 

 Lusus aquarum Dum^ril, Bibron, and Dum^ril, Erp^tologie g6n6rale, vol, 9, 



1854, p. 178 (types and type locality as preceding). 

 Piscis ludricus Dum:6ril, Bibron, and Dum^ril, Erp6tologie g6n6rale, vol. 9, 



1854, p. 178 (type and type locality as preceding). 



Type.—BTit. Mus. Nat. Hist. 

 Type locality. — Mexico, Mexico. 



Range. — Valley of Mexico. Kecorded from Lakes Xochimilco and 

 Chalco. 



SIREDON LEBMAENSIS TayJor 



Siredon lermaensis Taylor, Univ. Kansas Sci. Bull., vol. 26, 1939 (1940), pp. 

 427-430, pi. 48.— Taylor and Smith, Proc. U. S. Nat. Mus., vol. 95, 1945, 

 pp. 525-526. 



Type.— ERT-B.MS No. 22578. 



Type locality. — Lake Lerma, east of Toluca, Mexico, Mexico. 



Range. — Known only from the type locality. 



Genus RHYACOSIREDON Dunn 



Rhyacosiredon Dunn, Proc. New England Zool. Club, vol. 10, 1928, pp. 85-86. 



Genotype. — Amblystoma altamirani Duges. 



Range. — The high mountains at the southern edge of the main 

 Mexican plateau. 

 Species. — Four. 



KEY TO SPECIES OF RHYACOSIREDON 



Adults 



1. Tail about as long as body (less than 5 percent longer); elevation of tail 



in tail length 3.8 to 5 times; pterygopalatine-vomerine series average 

 about 18 teeth on each side; maxillary-premaxillary teeth about 31 on 



each side; when limbs are adpressed, toes touch elbow rivularis (p. 9) 



Tail longer than head and body by more than 5 percent; elevation of tail 

 in tail length from 6 to 9 times 2 



2. Mouth strongly papillate; toes not reaching elbow of adpressed limb, 



leorae (p. 9) 

 Mouth not obviously papillate; toes of adpressed limbs reaching elbows or 

 beyond altamirani (p. 9) 



Larvae 



1. Lips and tips of toes whitish or cream; body nearly uniformly colored 



(known only from larvae) zerapoalaensis (p. 9) 



Lips and tips of toes not whitish; body dark, strongly mottled with 

 cream rivularis, leorae, altamirani (p. 9) 



