Pacific Coast of North America. 179 



25. Sphceronia ampUcaudaj Stimpson. 



SphcBroma amplicauda, Stimpson, Proc. Bost. Soc. Nat. Hist. vi. 1857, 

 p. 89. 



Hah. Tomales Bay, California. 



Stebbing ^ suggests that a new genus near Cychidura 

 may be required for this species. 



26. Sphceroma rJwmhurum, sp. n. 



Surface of body punctate ; colour whitish yellow. 



Head small. First pair of antennae reach almost to the 

 posterior margin of the tir.st 

 thoracic segment. Second pair Fig- 12. 



of antenna extend quite to the 

 posterior margin of the first 

 thoracic segment. Eyes situated 

 post-laterally. 



Thoracic segments equal in 

 length. Epimera broad and 

 short, extending downwards, Sphceroma rhomburum. x \^. 

 forming an angle with the seg- Abdomen, 



ments. 



First abdominal segment as long as any of the thoracic 

 segments, crossed by suture-lines and surmounted by two 

 tubercles, close together, one on either side of the median 

 line. Terminal segment with its extremity produced in a 

 process rhomboid in shape and with sides infolded, forming 

 a kind of funnel-like opening when seen from beneath. At 

 the base of this segment are two tubercles, which are con- 

 tinuous with two longitudinal ridges in the centre of the 

 segment. These ridges unite near the extremity and con- 

 tinue as one median ridge. The uropoda are shorter than the 

 terminal segment ; the outer branch is more lanceolate in 

 shape ; both are of equal length. 



Two specimens were taken at Monterey Bay, California, 

 by Mr. Heath. 



Type, No. 22573, U.S. N. M. 



This species is near S. egregium, Chilton t, fi'om Arakoa, 

 but differs in the presence of two tubercles on the first 

 abdominal segment, in the presence of two tubercles and two 

 longitudinal ridges uniting in a single ridge on the terminal 

 segment, and in the equality in length of the two branches 

 of the uropoda. 



* Hist. Crust. 1893, p. 364. 



t Trans. New Zealand Inst. xxiv. 1891, p. 269. 



