482 
MR. H. N. RIDLEY ON THE 
kindness of Prof. Liitken, has 228 + 19. Considering that tke 
number 247 + 15 given by Strauch 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, E. & L., is known to occur, as Prof. Liitken 
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. caeca 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. caeca 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. Midleyi 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. caeca than in 
A. Hidleyi. 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, tapering. Eostral small, triangular; nasals forming a 
short suture ; a pair of very large prgefrontals, 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 aunuli 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 
Tail 24 
Diameter of body 11 
