408 Mr. G. A. Bouleuger on the 



Several species, among them our most common starfish 

 {Asterias ruhens), I have been unable to examine. The 

 material of some of the species was rather scanty and was 

 from a single locality only. This was the case with Bentho- 

 pecten spinosus and Dytaster agassizi. The specimens 

 examined of these two species (see the table, p. 402) have a 

 disc-radius of 5-10 mm. and 6-12 mm. respectively*, and 

 seem to belong to the same year-class (group II.). The 

 question regarding the age of the starfishes therefore needs 

 further investifjation. 



XL. — Synopsis of the American Species of Rana. 

 By G. A. BouLENGER, F.R.S. 



(Published by permission of the Trustees of the British Museum.) 



I. Toes pointed or with slightly swollen tips. 



A. Glandular dorso-lateral fold absent or flat and ill-defined, or, if 

 narrow and prominent, not extending to the hip ; tympanum 

 at least f diameter of eye, usually much larger, especially in 

 males ; tibia 2J to 4 times as long as broad ; toes f to entirely 

 webbed; outer metatarsals separated by web nearly to the 

 base ; nasal bones in contact with each other or narrowly 

 separated. 



1. Male with internal vocal sacs; dorso-lateral fold absent or 

 flat and very indistinct. 



Vomerine teeth between the choanse (rarely 



just behind them) ; first finger as long as 



or a little longer than second ; tibio- 



tarsal articulation reaching t^-mpauum 



or eye ; heels meeting or slightly over- 

 lapping when the hind limbs are folded 



at right angles to the body; tibia 2^^ 



to 2^ times in length from snont to vent ; 



tip of fourth toe free ; no dorso-lateral 



fold R. catesbiana, Shaw. 



Vomerine teeth between the choanae ; first 



finger a little shorter than second ; tibio- 



tarsal articulation reaching tympanum 



* The material of Benthopecten spinosus has not a maximum; of 

 Dytaster agassizi, on the other hand, there is a marked maximum at 

 9-10 mm, comprising 18 individuals (or 52*9 per cent, of the total 

 number). 



