482 



MR. H. N. RIDLEY ON THE 



kindness of Prof. Lutken, has 228 + 19. Considering that the 

 number 247 + 15 given by Straucli is taken from a specimen in 

 the Paris Museum, received from the Copenhagen Museum as 

 from the island of St. Thomas, where only A. fenestrata (Cope) 

 = antillensis, P.. & L., is known to occur, as Prof. Lutken 

 kindly informs me, it is clear to me that the specimen with 247 

 annuli belongs to A. fenestrata. The number of annuli would 

 range, in A. cceca from 212 to 229, and in the present species 

 from 180 to 196. According to Strauch, the length of the labial 

 border of the first labial shield in A. cceca is about one half the 

 length of that of the second; on Peters's figure of the type 

 specimen, as well as in the Porto Eico specimen before me, it is 

 about two thirds ; in A. Bidleyi both are equal, or the former is 

 a little longer. The snout is longer and somewhat more pro- 

 minent, the tail thicker and more obtuse in A. cceca than in 

 A. Itidleyi. The ventral segments of the two median rows are 

 broader than long in the former species, the coloration of which 

 is also different. I have therefore no hesitation in establishing 

 a new species, which may be characterized as follows : — 



Prsemaxillary teeth 5 or 7, maxillaries 5-5, mandibulars 8-8. 

 Snout obtusely pointed, slightly prominent. Tail thinner than 

 the body, ta{3ering. Postral small, triangular ; nasals forming a 

 short suture ; a pair of very large praefrontals, followed by a pair 

 of much smaller frontals ; eye hardly distinguishable through the 

 ocular ; a postocular, no subocular ; three large upper labials, 

 the second and third forming a suture with the ocular ; lower 

 border of second labial as long as or a little longer than that of 

 the first, in contact with the second lower labial only ; mental 

 quadrangular, followed by a large seven-sided chin-shield, which 

 is much longer than broad ; three lower labials, second very large. 

 180 to 196 annuli on the body and 18 to 20 on the tail ; the 

 divisions of the annuli longer than broad, nearly equilateral on 

 the middle of the belly, but nowhere broader than long ; 16 to 

 18 divisions above, and 20 to 24 below the lateral line. Anal 

 shields six or eight. Prseanal pores four. Uniform brown or 

 dark purplish brown above, pale brown inferiorly. 



millim. 



Length to vent 



250 

 24 

 11 



Tail 



Diameter of body 



