PROCEEDINGS OP UNITED STATES NATIONAL MUSEUM. 45 



snake {Crotalus horridtis), having a broad flat top and an abrupt, almost 

 overhanging', profile at the snout; the upper jaw extending far beyond 

 the lower (1.^ hundredths of length), the interinaxillary teeth being 

 visible from below when the jaws are closed. This character, common 

 to all species of Lycodes, is extraordinarily prominent in L. paxiUus. The 

 end of the maxilla extends behind the perpendicular from the jjosterior 

 margin of the orbit, and the tip of the upper jaw curves strongly down- 

 ward. The length of the upper jaw (.083) is contained twelve times in 

 the length of the body, and is greater than the postorbital length of the 

 head. The tip of the under jaw curv^es strongly upward, and is received 

 entirely within the upper jaw. The distance from the tip of the snout to 

 the articulation of the mandible (.10) equals one-third of the distance from 

 the snout to the anal, and one-tenth of total length. The muscles of the 

 cheeks are enormously developed and protuberant, the width of the 

 head in this region (.08) equaling the length of its postorbital portion. 

 The width of the interorbital area (.015) is less than half the diameter of 

 the orbit (.035), which is equal to half the length of the pectoral fin (.07). 

 The eyes are placed high, their upper margins approaching* closely to the 

 line of its uj)per profile, their diameter included about four times in the 

 length of tlie head. The nostrils are situated nearly midway between the 

 orbit and the tip of the snout. 



Intermaxillary teeth in a single series ; a few teeth in a second line 

 behind the others, near the symphysis. Mandibular teeth in a single 

 series, except at the symphysis, where there are a few (about 9) teeth in 

 front of the main series. A few teeth clustered at the head of the vomer. 

 On the palatines a single series, about six on each side. The teeth 

 throughout are stouter than is usual in this genus, recurved and sharply 

 pointed. 



Dorsal fin inserted at a point less than one-fourth of the distance from 

 the. snout to the end of the tail, and very slightly behind the perpen- 

 dicular from the tip of the extended pectoral. 



Anal fin inserted in the i)erj)endicular from the twelfth dorsal ray, at 

 a point three-tenths of the distance from the snout to the end of the tail. 

 The vent is in the vertical from the tenth dorsal ray, its distance from 

 the snout equaling about four times the length of the pectoral. 



The pectoral is inserted at a distance from the snout about equal to 

 twice its own length. 



The ventral is inserted at a distance from the snout equal to six times 

 its own length, its tip extending back to the line of insertion of the 

 pectoral. 



Scales covering the whole body and extending far out on the bases of 

 the dorsal and anal fins; head and pectoral fins scaleless. 



The color was probably light brown in life. 



Radial formula : — D. (including half of caudal), 116-117. A. (includ- 

 ing half of caudal), 100. P., 10. V., 3. 



