1 10 RATHBUN 



with ova (U. S. National Museum, No. 25,692). This species represents 

 a more northern latitude than any Alpheid hitherto described. 



Affinities. — The species differs from B. longidactylns Lockington in 

 its small hands, non-gaping fingers devoid of teeth, in the relative lengths 

 of the carpal segments of the second pair of legs, in the shorter antennular 

 spine, in the unequal peduncular joints of the antennulae, as well as in 

 some minor respects. ^ 



Family LYSMATIDyE. 



Genus Processa Leach. 



PROCESSA CANALICULATA Leach. 



Processa canaliculata Leach, Mai. Podoph. Brit., pi. XLI, and correspond- 

 ing text, July I, 1815. — Rathbun, Bull. U. S. Fish Comm. for 1900, 

 vol. II, p. 104, 1 901, and synonymy. 



Two specimens of unusual interest were taken at San Diego, Califor- 

 nia, 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 chelipeds 

 present. The other is so mutilated 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 locahty 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 or nearly 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 anten- 

 nulse varies from one and a 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 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, 1 5 fathoms. 



1 The type of B. harrimani has been compared with Dr. Holmes's description of B. 

 hngidactyhis (Occas. Papers Calif. Acad. Sci., vil, 190, 1900), specimens of that 

 species not being at hand. 



