REPORT ON THE CRUSTACEA MACRURA. 137 



differs from that in the male in being imperfectly chelate instead of terminating in a simple 

 styliform dactylos. The propodos is long, fringed with very long hairs on the internal 

 margin, and terminates abruptly. It is only on close inspection that the dactylos is found 

 to be present. The distal extremity of the propodos is produced to a blunt, internally 

 hollowed pollex. The dactylos is not longer than the pollex, flat, double-pointed, blunt, 

 and fringed with a few hairs. 



The branchiae are in accordance with others of the genus, and may be tabulated as 

 follows : — 



Pleurobranchiae, . . . 



Artbrobrancbias, . . . 



Podobranebije, . . . 



Mastigobrancbise, . . . 



b 



The first pair of pleopoda in the male is two-jointed (fig. 1 Z , p-p-) ', the basal joint is 

 cylindrical, the next commences as a small stalk and suddenly expands into a broad thin 

 spoon-like plate, the convex surface of which presses against the ventrum. They meet 

 in the median line, the inner margin of one overlying that of the other to form a hollow 

 groove, in which, I presume, the flexile extension of the membranous organ of the male 

 animal is supported at certain periods. 



In the female this same pair of pleopoda (fig. 1 p, $) is long, slender, compressed, and 

 fringed with fine hairs. 



The second pair of pleopoda (fig. 1 q, $ ) consists of a long, straight, basisal joint, that 

 supports two flattened branches, to the inner margins of which, in the male, two rigid 

 stylamblydes are attached. In the female (fig. 1 q, $) it resembles that of the male except 

 that it carries a single stylamblys, as is the case in both sexes in the several succeeding 

 pairs of pleopoda, except the sixth, which combines with the telson to make a broad and 

 well-formed rhipidura. 



Observations. — There were six specimens of this species taken about 100 miles 

 south-east' of the Fiji group of islands, associated with Pentacheles euthrix and 

 Benthesicymus. Two were 80 mm. and 85 mm., and three from 37 mm. to 40 mm. in 

 length. Of the larger, one is a male, the other a female. The above description has 

 been drawn from the male or smaller of these two specimens. Of these smaller specimens 

 the largest one is a male, characteristically though not fully developed ; the two others 

 are females. The vulva in each is apparent ; the form of the first pair of pleopoda, as 

 characteristic of the female, is distinguishable in each, and there is but a single 

 stylamblys on the second pair of pleopoda. In connection with the smaller female.-, 

 the posterior pair of pereiopoda terminates in a single styliform dactylos, a condition 

 that is characteristic of the male. I am therefore induced to believe that the chelate 

 structure in the female only exists in adult forms, or in those approaching maturity. 



(ZOOL. CHALL. EXP. PAET LII. — 1886.) Fff 18 



