414 BOULENGER. 



ous help of Miss Dickerson, Dr. Stejneger and Dr. Barbour to whom 

 I beg to express my best thanks. I have also been able to examine 

 the types of the Central American species preserved in the Paris 

 Museum and assign them their place in the synonymy. 



A few words of explanation are necessary concerning the method of 

 taking measurements. 



The length of the head and of the snout are measured along the axis, 

 and the posterior extremity of the head corresponds to the articu- 

 lation of the skull with the vertebral column, which can be approxi- 

 mately ascertained, in the flesh, by feeling with the points of the 

 compasses. The width of the head is the greatest width at the 

 commissures of the jaws. 



The tympanum, of which the greatest diameter is given, is com- 

 pared with the eye, measured along the side of the head. 



The limbs are measured fullv stretched out, the hind limb from the 

 middle line of the thigh where it joins the body. By foot is meant 

 the foot without the tarsus; it is measured from the tarso-metatarsal 

 articulation. Each finger or toe is measured from the point at which 

 it joins its fellows, and if this is not the same on both sides of it, as in 

 the case of the fourth toe, from the point most remote from the tip. 

 The length of the first toe is reckoned from the distal extremity of 

 the base of the inner metatarsal tubercle. 



Synopsis of the Species. 



I. Toes pointed or with slightly swollen tips. 



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

 if very prominent, not extending to the hip; tympanum at 

 least f diameter of eye, usually much larger, especially in males ; 

 tibia 2^ to 4 times as long as broad ; toes f to entirely webbed ; 

 outer metatarsals separated 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 (rarely just behind) the choanse; first finger 

 as long as or a little longer than second ; tibio-tarsal articulation reach- 

 ing tympanum or eye; heels meeting or slightly overlapping; tibia 

 2iV to 2^ times in length from snout to vent; tip of fourth toe free; 



no dorso-lateral fold R. catcshiana, Shaw. 



Vomerine teeth between the choan^e; first finger a little shorter than 



