1921 ] Schmitt: The Marine Decapod Crustacea of California 81 



Genus Processa Leach 



One of the first pair of legs chelate and the other simple; rarely both chelate. 

 Second pair of legs unequal, carpus multiarticulate. Rostrum short. 



Processa canaliculata Leach 



Plate 12, figure 6 



Processa canaliculata Leach, Mai. Podoph. Brit., pi. 41 and corresponding 

 text, July 1, 1815; Rathbun, Bull. IT. S. Fish Comm., 20, pt. 2, 104, 

 1900 (1901); H. A. E., 10, 110, 1904. 



Characters. — Rostrum slender, about half as long as eye-stalks, unarmed 

 except at apex, which is obscurely bifid and furnished with a few long hairs. First 

 pair of feet rather stout, reaching a little beyond the antennal scale ; right, or 

 chelate foot with palm a little longer than carpus or fingers ; left or simple foot 

 of first pair with dactylus about one-fourth the length of propodus ; remaining 

 feet slender; second pair unequal. 



Dimensions. — See Remarks. 



Type Locality. — Torcross, southern coast of Devon, England. 



Distribution. — Europe; Madeira; Bermudas; from North Carolina to Trini- 

 dad, including Gulf of Mexico and West Indies; from San Diego, California, to 

 Panama Bay; Japan; Amboina. Shallow water to 111 fathoms (Rathbun). 



Remarks. — From Miss Rathbun (1904a, p. 110), I take the following: 



Two specimens of unusual interest were taken at San Diego, California, by 

 D. S. Jordan, in 1880. They are about 22 mm. long, and differ from typical 

 specimens in having the left foot of the first pair similar to the right, or chelate. 

 One specimen is a female and has both ehelipeds present. The other is so muti- 

 lated that the sex is indeterminable; it has a left cheliped, the right is missing. 

 This form might perhaps be deemed a distinct species or genus were it not that 

 among a lot of specimens from Cedar Keys, Florida, both forms occur. From 

 this locality they are small (12 to 15 mm. long), and five specimens are bichelate 

 while four have only a right cheliped, the left foot being simple, as in typical 

 P. canaliculata. These two forms from the same locality present no other 

 appreciable difference. 



Aside from this remarkable dimorphism in the left first foot the species is a 

 most variable one. The rostrum may be half as long as the eye. The eyes while 

 always of good size are not uniform, in some cases larger and more reniform, 

 with the cornea extending on the outer side almost back to the carapace. The 

 second joint of the antennulae varies from one and one-fourth to twice the length 

 of the third joint. The antennal scale may be a little more than half as long as 

 the carapace (rostrum excluded) or even two-thirds as long as the carapace; it 

 may be just as long as the antennular peduncle or distinctly longer. Of the speci- 

 mens examined, those from the west coast of Mexico and Panama Bay have the 

 largest eyes ; they agree fairly well with the description and figure of Bate 's 

 P. processa from Amboina, 15 fathoms. 



Family Cragonidae (Ceangonidae) 



(Crangonidae of Authors, not Crangonidae page 73.) 



Rostrum generally small, usually dorsally flattened, and not toothed, or want- 

 ing; in Paracrangon only it is a subereet, elongated, laterally compressed spine. 

 Eyes generally free, in Nectocrangon only are they covered by the carapace. 

 Mandibles without incisor and palp. First pair of legs subchelate and stouter 

 than the second. Second pair slender and equal, with unsegmented carpus, either 

 minutely chelate or simple. 



