ZooL.-VoL. III.] HOLMES— ON SPHMROMIDS AND DYNAMENE. 30I 



the first basal joint enlarged, oblong, and emarginate at the distal end at 

 the insertion of the small, subquadrate second joint; flagellum longer than 

 the peduncle and composed of 9-1 1 joints. Second antennae scarcely reach- 

 ing the middle of the thorax, the peduncle slender, the last 2 joints much 

 longer than the preceding ones; flagellum a Httle longer than the peduncle, 

 the joints furnished with short setae. Thoracic legs increasing slightly in 

 length posteriorly and furnished with short hairs; propodi armed below 

 with spines; dactyls curved and ending in a spine with a strong spine 

 behind the tip. 



i^^wa/^ .•— The females are smaller than the males; the head, antenna, 

 mouth parts, thoracic legs, and anterior segments are not distinguishable 

 from those of the male, but the abdomen is markedly different. The caudal 

 shield is relatively smaller and less sculptured, the notch at the extremity is 

 simple and shallow; there are 3 oblong tubercles on the anterior portion; 

 the 3 tubercles on the next segment in front are smaller than in the male. 

 The branches of the uropods are flattened and of subequal size; neither 

 extends beyond the tip of the caudal shield. 



Both sexes possess the power of rolling themselves up, but they do not 

 take on so nearly a spherical form as that assumed by the species of 

 Sphcsroma. This species was taken from pieces of sponge dredged in 

 shallow water at San Clemente Island, August, 1893. In July, 1895, I col- 

 lected several specimens at San Diego, California. The 2 sexes were found 

 together and were associated with no other species of Sphasromid. It was 

 inferred from the association of these forms and their similarity in all external 

 features except in the posterior part of the body, that they represented the 

 male and female of the same species, but this conclusion was confirmed by 

 the dissection of several specimens. The males, however, may be distin- 

 guished in this species, as in other Sphaeromids, by the possession of a 

 stylet on the second pair of pleopods. None of the females were found 

 bearing eggs, though the ovaries were well developed and the vasa defer- 

 entia of the males were distended with spermatozoa. 



The male of this species is very closely allied to the 

 form recently described by Miss Richardson ^ as Cilic(Ba 

 caudata gilliana. It differs in having a single median 

 spine, instead of a pair of spines, at the anterior end of the 

 emargination of the caudal segment, and in having usually 

 but a single pair of teeth, instead of three pairs, at the sides 

 of this emargination. In some cases, however, the posterior 

 angles of the emargination may be dentiform and partly 

 included so as to give rise to two pairs of lateral teeth. The 

 inner branch of the uropods presents a prominent angle 

 which stands some distance away from the sides of the 

 caudal segment, while the point of the ramus in cmidata 



1 Proc. IT. S. Nat. Mus. v. 21, p. 840, fig. 17, i8gg. 



