218 CALIFORNIA ACADEMY OF SCIENCES. 



chelate and furnished with small exopods and increasing in length pos- 

 teriorly. No podobranchise. All the abdominal appendages bear two 

 foliaceous branches except the last pair which, in the male, carries attached 

 to the base a large, membranous appendage, which in the female is reduced 

 to a rudiment. 



Penaeus calif orniensis, sp. no v. 



Pen(Bus canaliculatus Holmes (not Olivier), Proc. Cal. Acad. Sci. (2), Vol. 

 IV, 1895, p. 581. 



Eostrum slender, acuminate, slightly arched, the upper margin ciliated 

 and armed with nine or ten teeth, the last tooth on the gastric region and 

 separated by an unusually wide interval from the preceding tooth; lower 

 margin with two small teeth; the rostrum is continued backward upon the 

 carapace as a carina nearly to the posterior end, its dorsal surface sulcate 

 posterior to the last tooth; on either side a prominent groove which ter- 

 minates abruptly a short distance in front of the posterior margin of the 

 carapace; the outer margins of these grooves spread outward near the last 

 rostral tooth and are continued anteriorly npon the lateral ridges of the 

 rostrum. Above the base of the antennae there is a strong marginal spine 

 which is continued backwards into a carina; above this is a wide, oblique 

 groove, at the posterior end of which is a small hepatic spine; a narrow 

 groove, running obliquely downwards, joins the wide groove immediately 

 above this spi^e. Antero-lateral angle of the carapace rounded, with a 

 sinus above. Antennuletr peduncle equalling or a little exceeding the 

 rostrum, the inner appendage of the first joint long, narrow and ciliated; 

 flagella much shorter than the peduncle. Antennal scale reaching about 

 as far forward as the tip of the rostrum; the flagellum may exceed the 

 length of the body. Chelipeds becoming more slender posteriorly and 

 increasing in length, owing mainly to the increase in the length of the 

 carpus; the second joint in the first two pairs has a spine at the distal end 

 of the lower margin, and there is a second spine in the first pair on the 

 lower side of the ischium; the chelae become longer and narrower pos- 

 teriorly; the first is nearly as long as the carpus, while the third is scarcely 

 half as long as that joint; two posterior pairs of pereopods subequal. The 

 three anterior abdominal segments are not carinated above; the fourth is 

 carinated at least on the posterior portion; fifth segment carinated, but 

 not ending posteriorly in a tooth; the carina on the sixth segment is acute, 

 with a groove on either side, and terminates in a tooth at the posterior 

 end. Telson acute, about as long as the preceding segment, devoid of 

 lateral spines, and furnished with a conspicuous dorsal groove, which 

 extends from the anterior end to the tip. The uropods extend far beyond 

 the telson. 



