89 



the structure of the mouth-organs. In Part III. of the 12th 

 Report of the Fishery Board is a note setting forth the more 

 prominent of these differences — SabcUiphiliis inchided." 



The first four pairs of thoracic feet are biramous, the stronger 

 showing externally three joints, the distal segment being some- 

 what ovoid, and furnished with strong spines. The next segment 

 also has a long spine — the other has an elongated terminal 

 segment. The fifth pair appears to be rudimentary — probably 

 represented by the lateral processes of the narrow segment in 

 front of the genital segment (the first abdominal of some e.g. 

 Claparede).* This segment has the enlarged vulva^ to which 

 in the sketch the ovisacs adhere (Plate IX., fig. 56). These are 

 distended with moderately large eggs. In some the ova were 

 still in the ovaries, though ready for deposition, and in one 

 filmy tissue adhered to the vulvae — either for the purpose of 

 receiving the ova on discharge, or which had been left after the 

 escape of the eggs from the ovisacs. Moreover, in several a 

 spermatophore was attached to the pigmented tissue of the vulva 

 on one side, but was detached during examination (Plate IX., 



The male is less than the female, measuring "7239 mm., and is 

 proportionately more elongated (Plate IX., figs. 51 and 52), all the 

 segments of the body being narrower. The antennules (Plate 

 IX., fig. 53) agree in regard to the proportions of their segments 

 with those in the female and so with the antennie (Fig. ibidem). 

 The other appendages of the region also correspond. In lateral 

 view (Plate IX., fig. 52 ) the four anterior thoracic feet are more 

 distinctly observed, and the shape of the rostrum is more clearly 

 defined. The genital and caudal segments, however, do not 

 readily take this posture, so that they are generally seen in a 

 horizontal position — not on edge — probably because the genital 

 segment, which is flattened from side to side, maintains this 

 position. The condition of the genital segment at once dis- 

 tinguishes this sex, for it is broadly ovate, convex in front, but 

 somewhat concave posteriorly. It contains an ovoid spermato- 

 phore on each side, and the apertures appear to be posterior, each 

 debouching from a papilla. On extension the spermatophore is 

 spindle-shaped (Plate IX., fig. 54). It however assumes a different 

 aspect after the sperms have been utilized (Plate IX., fig. 55) for 

 then the elasticity of its capsule gives it an elongated slipper- 

 shape. The chitinous investment of the genital segment seems 

 to lend itself more readily to its varying contents than that of 

 the other parts — a feature probably due to its delicacy. As in 

 the female, four caudal segments succeed the genital — each 

 being slightly narrower than the one in front, and the last being 

 somewhat longer. It bears the two elongated processes from 

 which the spines extend. 



* Ans. Sc. Xat. 5th Se. XIII p. 14. 



