12G BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 



much reduced, aud the snake like form of oue of the species. The species 

 are four, as follows : 



I. Costal plicBB, eighteen; the toes well developed, palmate. 



Outer posterior toe well developed ; hiud limb extending over 7.5 costal inter- 

 spaces, fore limb to orbit ; tail equal body and head to orbit, more slender than 



the body; belly yellowisli ^ B, pacificua. 



II. Costal plicfp, nineteen to twenty-one ; toes very rudimeutal, little distinct. 

 a. Parasphenoid teeth in one patch. 

 Hind limb extending over six costal interspaces ; fore limb nearly to orbit ; tail 

 as long as body and head to orbit; width of head seven times from muzzle to 



groin; belly black B. nigriveniris^ 



Hind limb extending over four costal interspaces ; fore limb not to angle of 

 mouth ; tail thick as body, as long as body and head plus the length from 

 muzzle to axilla ; width of head eight times from muzzle to groin ; belly 



brown B. attenuatus. 



aa. Parasphenoid teeth in two patches. 

 Hind limb extending over four costal spaces ; tail more than twice as long as 

 head and body ; sides dark ..B. caudatus. 



BATEACHOSEPS CAUDATUS Cope. 

 (Plate Lxxxi, fig. 2.) 



Head short, wide, muzzle as long as eye, the nostril not quite ter- 

 minal. Length from end of muzzle to humerus entering 3.33 times in 

 length from humerus to axilla. These proportions are those of the 

 B. attenuatus. Tail excessively elongate, 2.2 the length of the head 

 and body. In the B. attenuatus the tail is 1.6 the length of the head 

 and body and less (measurements made from femur). Limbs about as 

 in B. attenuatus, the anterior reacliiug the first dermal groove behind 

 the mouth, and the posterior covering four intercostal spaces when ex- 

 tended forwards. The inner digits are rudimental, that of the anterior 

 foot possessing a metacarpus only. The costal grooves number twenty- 

 one; they extend across the abdomeu, but are not visible on the back. 

 The tongue is a longitudinal oval. The vomerine teeth form two con- 

 vergent brands directed inwards and posteriorly from within the choanne. 

 They are better developed than in B. attenuatus. The parasphenoid 

 teeth are in two distinct patches, thus differing from those of the B. 

 attenuatus, where they form a single patch. 



Measuremerits. 



M. 



Total length , .160 



Length to axilla 0115 



Length to groin 051 



Length to base of tail , 057 



Width of head 006 



Length of fore limb 0065 



Length of hiud limb 007 



The general color is brown. It is deeper on the sides to a line on 

 each side of the back and on the anterior half of the abdomen aud on 

 the superior surface of the distal part of the tail. Gular region and 

 chin yellowish. 



