412 Ml-. G. A. Boulengei- on the 



2. Tips of fingers obtuse or ratlier pointed; vomerine teeth be- 

 tween cboanae ; tympanum -^ to f diameter of eve ; tibio- 

 tarsal articulation reaching eye or tip of snout ; tibia If to 

 21- times in length from snout to vent ; dorso-lateral fold 

 prominent, its distance from its fellow, on the back, 4 to 5^ 

 times in length from snout to vent; no outer metatarsal 

 tubercle ; head as long as broad or a little broader than long ; 

 male with internal vocal sacs . . li. palmipes, Spix. 



B. Loreal region vertical or nearly so ; toes f to | webbed ; tips of 

 fingers swollen ; tympanum 5 to § diameter of eye ; tibio- 

 . tarsal articulation reaching eye or between eye and tip of 

 snout ; heels overlapping ; tibia to 6 times as long as broad, 

 If to 2 times in length from snout to vent ; dorso-lateral fold 

 prominent, its distance from its fellow, on the back, 5 to 6 

 times in length from snout to vent ; no outer metatarsal 

 tubercle ; head as long as broad or a little longer than broad ; 

 male without vocal sacs H, ccerideoimnctata, Stdr. 



The American frogs all belong to the subgenus Rana, 

 agreeing with the type-species, R. temporaria, L,, in the 

 structure of the pectoral arch (strong horizontal clavicles, 

 oraosternal style not forked at the base). I conceive the 

 most primitive type as with large nasal bones in contact 

 with each other and with tlie frontoparietals entirely cover- 

 ing the ethmoid ; pointed^ f^iHv webbed toes with the outer 

 metatarsals separated by web to the base ; a distinct tym- 

 panum ; no glandular dorso-lateral fold*. I therefore 

 regard the species grouped together in division I. A. of the 

 above synopsis as nearest to this prototype ; from this group 

 I. B, 1. and II. seem to be directly and independently derived, 

 probably also I. B.2. 6. ; whilst I. B. 2. a. is obviously con- 

 nected with I.B.I. The s])ecies under Division II. are 

 furthest removed from the prototype ; I see no reason for 

 regarding R. boylii as nearly allied to the Ranee teniporaricBj 

 and it is connected with R. palmipes by R, pustulosa. 



1. Rana catesbiatia, Shaw, 1802. 



JR. boons (non L.),Lacep., 1788. — JR. nwffiens, Merr., 1820. — A. scapxi- 

 laris, 2iipiens, Harl., 1825. — R. conspersa, Leconte, 1855. 



North America east of the Rocky Mountains, from Canada 

 (Quebec, Ontario) to Florida and Texas. 



2. Rana grylio, Stejneg., 1901. 

 Florida, Mississippi, and Louisiana. 



* Cf. Bull. Soc. Zool. France, 1918, p. 111. 



