280 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



A number of individuals were found at Monterey Bay, California, 

 and sent to the U. S. National Museum by Mr. Heath, who gives the 

 following note of their habits: 



They were taken by the Chinese fishermen from a sandy sea bottom about 30 feet 

 below the surface (according to the Chinese statement). These are rapid swimmers, 

 and the moment they are disturbed they roll into a ball and project the exopodite 

 of. the last free segment. This is undoubtedly for protection. I have not had time 

 to accurately examine the position nor character of this appendage, but its sharp, 

 swordlike nature is readily recognized. 



Type. Cat. No. 22572, U.S.N.M. 



This species differs from T. alascensis in having longer antenna and 

 antennulse; in having the terminal segment rounded, which in that 

 species is very pointed; in having the outer branch of the uropods as 

 short as the inner, which in that species is much longer; in having only 

 a gradual increase in the length of the legs, which in that species show 

 such marked disproportions in the propodus of the sixth and seventh 

 pairs, and in the position of the eyes, which in this species are situated 

 in the median transverse line of the head, while in T. alascensis they are 

 placed in the posterior half of the head. 



48. Genus SPH^EROMA Latreille. 



Body contractile, able to roll into a complete ball. Abdomen com- 

 posed of two segments, the first of which is formed by the fusion of 

 several coalesced segments. The terminal segment is rounded, entire. 



The branches of the uropoda are similar, both being salient. The 

 outer branch of the uropoda is denticulate along the exterior margin; 

 the inner branch is immovable and fixed to the side of the abdomen; 

 the outer branch is movable, and capable of folding under the inner 

 branch. 



The second, third, and fourth articles of the palp of the maxillipeds 

 not produced into lobes, but furnished with exceedingly long hairs. 



Legs all ambulatory in structure. 



ANALYTICAL KEY TO THE SPECIES OF THE GENUS SPH^ROMA. 



a. Abdomen without tubercles Sphseroma quadridentatum Say 



a'. Abdomen with tubercles. 



b. Tubercles on terminal segment of abdomen arranged in a transverse row of four 

 on anterior portion. Two tubercles on first abdominal segment, one on either 

 side of the median line. A transverse row of four tubercles, two on either 

 side of the median line on the seventh thoracic segment. Posterior extremity 

 of terminal segment of abdomen without prominent transverse elevation. 



Sphseromn destructor Richardson 



b'. Tubercles on terminal segment of abdomen arranged in two longitudinal series 

 of four, a series on eithe.r side of the median line. No tubercles on first seg- 

 ment of abdomen or on seventh thoracic segment. Posterior extremity of ter- 

 minal segment of abdomen with prominent transverse elevation. 



Sphssroma pentodon Richardson 



