MUSEUM OF COMPARATIVE ZOOLOGY. 85 



merus, the latter twice as long as the former, a still more slender carpus nearly 

 as long as the merus, and a portion of an exceedingly slender and filiform 

 propodus. 



The abdomen (PL XIV. fig. 1) to the tip of the telson is nearly twice as 

 long as the carapax, anteriorly about as broad as high, but much compressed 

 posteriorly, so that the sixth somite is fully twice as high as broad. The 

 dorsum is evenly rounded on the first four somites, but there is a narrow and 

 sharp carina on the fifth and sixth, which rises abruptly into a crest on the 

 anterior part of the fifth. The posterior prolongations of the first and second 

 epimera are broadly rounded ; those of the third and fourth less broad and 

 more angular, but still obtuse and rounded at the posterior angle ; while the 

 fifth is acutely angular, but with the tip itself obtuse. The sixth somite is 

 twice as long as the fifth, and more than half as high as long. The telson 

 wants the tip, but is apparently shorter than the sixth somite ; it is narrowly 

 triangular, thickened and transversely very strongly convex above at base, but 

 not carinated, and posteriorly flattened above. 



The lamellae of the uropods are thin and lanceolate in outline. The inner 

 is only a little shorter than the sixth somite, less than a third as broad as long, 

 and stiff'ened in the middle by two slender riblike thickenings, separated, on 

 the dorsal surface, by a narrow sulcus. The outer is fully once and a half as 

 long as the inner, scarcely a fourth as broad as long, and the narrow tip is pro- 

 longed far beyond the sharp spine in which the thickened outer margin termi- 

 nates, and from this spine a slender riblike thickening, with a narrow sulcus 

 along its inner edge on the dorsal surface, runs nearly parallel with the outer 

 edge to the base of the lamella. 



The abdominal- appendages of the first pair are as large as those of the second, 

 about as long as the uropods, and the distal raultiarticulate portion h nearly 

 twice as long as the protopod, slender and subcylindrical. The peculiar male 

 ■appendage (petasma of Bate) is a thin, squarish plate (PI. XIV. f^g. 7) attached 

 by a constricted base, below which there is a small oblong process (a) standing 

 out at nearly right angles to the plane of the rest of the plate. The plate 

 itself, which is apparently carried in a nearly horizontal position in front of 

 the protopod to which it is attached, is obliquely divided vertically or longi- 

 tudinally by imperfect articulations into three parts, of which the middle one 

 is much the largest and projects at the inner inferior angle in a large ovately 

 pointed process, while the inner or distal of the three parts is narrow and has 

 the lower or posterior part of its free edge armed with minute hooked spines 

 for the attachment of the appendages of the opposite sides of the animal. The 

 outer rami of the second to the fifth pairs of abdominal appendages are similar 

 to the single rami of the first pair, but are all considerably compressed distally. 

 The inner ramus in the second pair is very much more slender and considerably 

 shorter than the outer, and is furnished on the anterior side at base with two 

 small and obtusely terminated, hard, lamelliform processes. The inner rami 

 of the third, fourth, and fifth pairs of appendages are as in the first pair except 

 that they are without the lamelliform process at base. 



