PROM THE INLAND SEA OF JAPAN". 433 



reach just beyond the iscliium, whereas those of the first reach nearly to the distal end of 

 the merus. 



Geogi-apJiical Distribution. — West coast of the island of Yezo, near Cape Sooga, 

 lat. 45° N. {de Haan); Hizen, Nagasaki (jRathbun). 



PENiEUS (Metapen^us) akatebi, Rathbun. (PI. 33. fig. 54.) 



Pen<EUS velutinus, Spence Bate, 'Challenger' Macrura, 1888, p. 253 (part.), nee Pen. velutinus, Dana. 

 Penceus velutinus, Kisbiuouye, in Journ. Fish. Bureau, Tokyo, viii. no. 1, 1900, p. 20, pi. 6. fig. 2 ; 



pi. 7. figs. 11, 11 «, 116. 

 Parapenaus akayebi, Rathbun, in Proc. U.S. Nat. Museum, xxvi. 1902, p. 39. 

 ? Mctapenteas stridulans, W.-Mason, Alcock, in Ann. & Mag. Nat. Ilist. ser. 7, xvi. 1905, p. 526. 



One male and one female from the Inland Sea of Japan, caught in deep water. 



According to the label, this species, which is very comtuon, has carious pea-green 

 eyes, the body covered with red mottled spots. 



The male is 57 mm. long from tip of rostrum to the end of the telson ; the carapace 

 with the rostrum is 17"5 mm. long, without the rostrum 10 mm. ; the sixth segment of 

 the abdomen, measured on median line, appears to be 8'75 mm. long, 4-6 mm. broad 

 anteriorly, 3"7 mm. broad posteriorly. The rostrum, which reaches to the end of the 

 second joint of the antennular peduncle, is horizontal and 1 + 6-toothed; the gastric 

 tooth is situated at the anterior fourth of the carapace, as in Kishiuouye's figure; 

 according to Miss Rathbun, it should be situated in adult individuals " a little in front 

 of the anterior third " ; the foremost tooth is a little farther from the tip than from 

 the penultimate. The telson, which is little longer than the sixth segment, is armed 

 with one immovable spiniform tooth, which is preceded by three movable spines. 



The short flagella of the inner antennae are little more than twice as long as the 

 terminal joint of their peduncle; they are of equal length, but the vipper is much 

 stouter than the gradually tapering lower flagellum, and they reach entirely beyond the 

 antennal scales. 



The external maxilUpeds extend almost to the tip of the rostrum ; their exopodite 

 reaches to the middle of the merus. 



All the thoracic legs carry an exopodite. 



The female is GO mm. long; the carapace, rostrum included, 19'5 mm., without it 

 11 mm. ; the sixth segment of the abdomen is, measured on median line, 9-5 mm. long, 

 5 mm. broad anteriorly, 4 mm. posteriorly ; the telson, 9"75 mm. long, has its lateral 

 margins armed as in the male. The very slightly ascending rostrum, which reaches to 

 the end of the second joint of the antennular peduncle, is 1 + 7-toothed ; the three or 

 four anterior teeth decrease a little in size, and the anterior tooth is a little farther 

 from the tip than from the penultimate, whereas the gastric tooth is situated at tlie 

 anterior fourth as in the male. 



The external maxillipeds and the thoracic legs egree with those of the male; those of 

 the fifth pair carry also an exoj)odite. 



Both in the male and in the female the carapace carries a pair of stridulating-organs, 

 first mentioned by Dr. Alcock in his description of 3Ieiaj)eu(eus slridulan.i (Ann. & Mag. 



