286 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



specimens have three strong plumose seta? and one that is feeble on 

 the inner plate, and nine spines on the outer plate of the tirst maxilhe. 



The terminal abdominal segment in Stebbing's specimens has the 

 sides near the apex incurved. In the Florida specimens the sides are 

 straight. 



The outer branch of the uropoda in S.' destructor has four teeth on 

 the exterior margin, and a slight indication of a fifth in some speci- 

 mens. There are never six teeth, and the fifth one is never well 

 developed and strong as the four, which are constant in size and num- 

 ber. Stebbing says that this number is also found in the Ceylon 

 specimens, the precise number being immaterial, but later, in pointing 

 out the affinity of Sphseroma felix Lanchester, with the species in 

 question, refers to the outer ramus in Sphseroma felix as having eight 

 small teeth on the outer margin, this being a character to be consid- 

 ered in separating the species. 



The second, third, and fourth segments of Sphseroma destructor are 

 each crossed by a transverse ridge. In Stebbing's specimens only the 

 fourth segment has a transverse ridge. 



The apical tooth of the mandibles is sub-bififl in the Florida 

 specimens. 



SPH^ROMA PENTODON Richardson. 



Sphseroma pentodon RICHARDSON, Harriman Alaska Exp. Crust., X, pp. 214-215; 

 Proc. U. S. Nat. Mus., XXVII, 1904, pp. 659-660 HOLMES, Proc. Cal. 

 Acad. Sciences (3), III, 1904, pp. 323-324, pi. xxxvn, fig. 43. 



Localities. Sausalito, San Francisco Bay, California. Found in 

 mud flat. 



Body elliptical in outine; color dark brown; sur- 

 face minutely but densely granular. 



Head situated transversely, with a prominent 

 ridge on the anterior margin. Eyes placed post- 

 laterally, and composed of many ocelli. First pair 

 of antennae extend to the posterior margin of the 

 head; flagellum eight-jointed. Second pair of an- 

 tennae reach the middle of the second thoracic seg- 

 ment; flagellum composed of fifteen joints. 

 FIG. 299. SPH.EROMA Segments of the thorax about equal in length, 

 up N E T D OD x'27| lAXIL with the exception of the first, which is somewhat 

 longer than any of those following. The lateral 

 parts, which are not distinctly separated from the dorsal portion of the 

 segments, are drawn out in acute processes in the first three segments. 

 Those of the following segments are more nearly regular in outline. 



The abdomen is somewhat broader than the thorax, although this 

 expansion of the abdomen does not show in a dorsal view. The first 



