184 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



fig. 25) of the female callianassae, and a stud}'' of the type material of 

 the latter (p. 165) has made it plain that Wilson was not dealing with 

 subadhaerens. 



It is necessary nonetheless to distinguish subadhaerens from thy- 

 sanotus. In life, a difference is easily seen since subadhaerens carries 

 the fourth legs characteristically at right angles to the ventral body 

 surface. It is possible to distinguish even the youngest stages that 

 I have examined in this way. Preserved adults can easily be sepa- 

 rated by the condition of the genital segment in the females and the 

 sixth legs in the males. It is only when dead immature specimens are 

 being sorted that one need resort to the key characters given (p. 165). 



Distribution: This species has been found from Nanaimo, British 

 Columbia, to Bodega Bay, California. The data available suggest 

 that both sexes are associated with Callianassa californiensis but 

 occur in the burrow rather than on the body of the animal. This 

 behavior is most clearly shown by the collection at C.6 on February 

 2, 1958, when 24 specimens were recovered from "burrow water" — 

 in this case about 200 cc. — and only 2 from 12 hosts. Only the 

 later developmental stages have been found. 



Hemicyclops elongatus Wilson 



Figure 8 



Hemicyclops elongatus Wilson, 1937, pp. 206-208, figs. 1-6.— Nicholls, 1944, p. 49 — 

 Sewell, 1949, pp. 68-69. 



Type and specimen examined: Holotype female, USNM 60431, 

 from gill cavity of Callianassa sp., Salaverry, North Peru, F. Sears, 

 October 21, 1926. This, the only known specimen, was examined 

 without dissection in alcohol. 



Redescription of the female: Habitus of body agreeing with 

 Wilson's description except that terga of prosomal segments now not 

 "closely imbricate" (compare Wilson's, 1937, fig. 1 and my fig. 8a) pos- 

 sibly due to shrinkage during prolonged immersion in alcohol. The ap- 

 parent fold in the exoskeleton at the anterior end of the cephalothorax 

 and the fact that my measurements make the body somewhat smaller 

 (length 2.7 mm. instead of 3.0 mm., 0.89 mm. wide rather than 0.90 



Figure 6.- — Hemicyclops subadhaerens, new species: a-d, Female: a, Habitus, dorsal aspect. 

 b, Right antennule, ventral (posterior) view, c, Left antenna, dorsal (posterior) view. 

 d, Oral area (without mouthparts), ventral view, e-i, Male: e, Habitus, dorsal aspect. 

 /, Left antennule, dorsal (anterior) view, g, Right antenna, dorsal (posterior) view, h, 

 Labrum, dorsal view, i, Right paragnath, ventral (posterior) view. Scale A (fig. 2) 

 applies to a and e; D to b and/; E to c-d and g-h; and G to i. 



