134 BULLETIN 84, UNITED STATES NATIONAL MUSEUM. 



The mouth shields are always divided into two unequal parts by a transverse 

 fissure. The external region, which is by far the more important, is sensibly wider 

 than long; it is semicircular, with an almost straight proximal side and a very 

 convex distal side. The proximal region forms a small triangle which wedges 

 between the two adoral plates on half their length; it is, in fact, the proximal angle 

 of the mouth shield which has got separated from the rest of the plate. The adoral 

 plates are fairly large, oval, or piriform. The oral plates are elongated and high, 

 almost twice longer than wide. The oral papillae amount to four on each side, 

 and their size rapidly decreases from the external papilla, which is large and wide, 

 to the last two which are small, low, and little distinct. The tooth papilla, which is 

 odd, is conical and a little larger than the foregoing one. 



The rather small upper brachial plates are swollen but not protruding; the 

 first three are transversely widened and their length increases from the first one, 

 which is very little developed, to the third; the latter is the largest of all; these three 

 plates are contiguous on a large portion of their adjacent sides. Beyond the third 

 one, the plates become triangular and about as long as wide, with a sharp proximal 

 angle and a very convex distal side; the fourth plate is still contiguous with the third 

 at its proximal angle, but, beyond the fourth, the plates are separated by an interval 

 which is at first rather short and then becomes a little more elongated. 



The first under brachial plate is pentagonal and a little longer than wide with 

 an obtuse proximal angle, diverging lateral sides, and a convex distal side. The 

 succeeding plates are very large, quadrangular, with a straight proximal side 

 much narrower than the distal side which is widened; the latter is at first convex 

 and then it is slightly notched in its middle; the sides are divergent. These plates 

 are wider than long and they are all contiguous. 



The largest portion of each lateral brachial plate is especially developed on the 

 upper face of the arms; these plates wedge between the successive dorsal plates; 

 their sides are parallel. The accessory piece is quadrangular, twice wider than 

 long, with rounded angles. 



The brachial spines, amounting to two only, are short and papilliform, lying 

 on the plate and a little longer than wide, with a rounded end; the ventral spine 

 is a little more widened than the other. 



The tentacular scale is fairly developed and well apparent; it is rounded and 

 flattened. 



The brachial plates are, as the other plates of the body, covered with minute 

 granules; these granules are a little more conspicuous on the lateral plates. 



The color of the two examples in alcohol is grayish. 



The smaller specimen corresponds fairly well to VerriU's description; it differs 

 from it chiefly by the large radial plates, which separate the proximal regions from 

 the radial shields. These plates already show a beginning of a protuberance 

 corresponding to the conical and protruding tubercle which I have referred to 

 above, and which does not yet exist on VerriU's specimen. The two radial shields 

 of each pair are also slightly converging distally; the centro-dorsal plate is very 

 distinct. The mouth shields have actually the same shape as in the adult, and 

 their proximal angle is separated from the rest of the plate (an arrangement which 

 Verrill does not mention, but which, however, seems to be indicated on his drawing). 



