S. I. Smith — Crustaceans of the Atlantic Coast. 
95 
the armament of the coronal extremities, with the mandibles of Par- 
erythrops obesa. In each mandible the inferior angle of the crown is 
separated by a broad space from the superior, or molar, angle. The 
inferior edges and the molar processes in both mandibles are almost 
exactly as in Parerythrops obesa: the inferior edge itself is much 
alike in the two mandibles, being composed of about four irregular, 
obtuse teeth, but the dentiform process just within the edge differs in 
the two mandibles ; in the right it is more slender and prominent 
than in the left, and enlarges at the extremity, which is armed with 
several rather slender teeth ; while in the left the process is shorter, 
stouter, and terminates in shorter teeth. The space between the 
armament of the inferior edge and the molar process is, in each man- 
dible, furnished with twelve to fourteen setiform teeth which are 
very different in the two mandibles: in the left they are slender, 
crowded closely together, and armed with minute, spiniform teeth'; 
while in the right they occupy a much largei; space, are thin, acutely 
triangular, and wholly destitute of secondary spines or dentations, 
except, possibly, one or two exceedingly minute’ spinules at the bases 
of a few of them. The mandibular palpi have almost precisely the 
same form, proportions, and armament of spines and set® as in Par- 
erythrops obesa. 
The first maxillae are throughout exactly as in Parerythrops obesa. 
The second, also, have very nearly the same form and proportions as 
in that species; the outer lobe, or scajdiognath, however, differs in 
being broadly oval, margined with twenty-five to thirty set®, and in 
having the anterior extremity rounded and tipped with four set®, 
two of which are very distinctly on the inner margin inside the tip, 
while in Parerythrops obesa the scaphognath is triangular anteriorly, 
is margined with only fifteen to eighteen set®, none of which are 
really on the inner margin, although there are two at the narrow tip; 
the three lobes of the protognath and the two segments of the palpus 
(endognath) are exactly as in Parerythrops obesa , except that they 
are furnished with a few more set®. 
The endognath in the maxillipeds is almost exactly like this part of 
the same appendage in Parerythrops obesa. The exognath differs 
in being very slightly larger proportionally and in having thirteen or 
fourteen segments in the flagelliform portion. The endognath in the 
first gnathopods (second maxillipeds) does not differ from the same 
part in Parerythrops obesa , except that it is armed with a somewhat 
greater number of set® and spines, particularly on the distal part of 
the outer margin of the longest segment (merits). The exognath is 
