REPORT ON THE AMPHIPODA. 1259 



are very short ; the first joint is much shorter than the second segment of the body, 

 and much shorter than the oval hand, which is only armed on the hinder longer margin 

 with two small teeth. The branchial vesicles are of an elongate oval form. The three 

 hinder pairs of feet are successively longer, and are shorter, with much broader joints, 

 than in C. linearis. That pair, which is attached to the fifth segment of the body, is 

 the shortest ; its first joint is only a Uttle longer than broad, and the lower hinder 

 angle is outdrawn into a spine ; the fourth joint is about as long as broad. The hand 

 is somewhat shorter than the preceding joints together and is somewhat more than 

 double as long as broad. The palm is furnished with setas. On the last legs the joints 

 are much longer and narrower." With this should be compared the description given 

 as follows by Stimpson : — 



" The body in this species is slender. The antennae are exceedingly variable in their 

 proportions; the flagella of the superior ones 10-15 articulate; inferior ones sub- 

 pediform. A more or less developed spine, which curves forward, and is sometimes of 

 considerable length, is placed upon the dorsal surface at the anterior extremity of the 

 first thoracic segment. Hand of the second pair of feet generally three-toothed on the 

 inner surface ; teeth (in full-grown specimens) about equal in size, and placed mostly 

 toward the outer extremity of the palm. Two or three sharp tubercles along each of 

 the sides of the branchiferous segments ; and a short dorsal spine on each of the three 

 posterior segments. Hands of posterior feet slender. Color, variable. Length, one-inch ; 

 breadth, about 0"03 inch. Found on seaweeds, etc., below low- water mark in San 

 Francisco Bay, near its entrance." 



It is probable that by " the anterior extremity of the first thoracic segment" 

 Stimpson intends the head. Boeck did not find in his specimens the sharp tubercles 

 on each side of the branchiferous segments, and does not consider that Stimpson's 

 description of the hand of the second gnathopods agrees with his own. 



Guerin-Meneville's Caprella tuberculata, 1836, and Lockington's Caprella spinosa, 

 1875, if the types are accessible, may eventually be found to belong to this species, or 

 to be varieties of it. 



As observed in the Challenger specimens, the male of this species attains a very 

 considerable length, measuring a good deal more than one inch without the antennse 

 and hind perseopods. The forward-directed horn on the short head is small ; the 

 proportions of the segments vary as usual with the size of the specimen ; in the 

 longest specimen the first segment measured not less than three-tenths of an inch and 

 was even longer than the second segment, though these proportions in other specimens 

 were reversed ; the suture between the head and the first segment seems to be almost 

 or quite continuous ; the second segment is much longer than the third ; the third is 

 subequal to the fourth, the two together longer than the second, and each having a 

 small dorsal tooth at the extremity, though in some specimens this, especially on the 



