FEOM THE ITs-^LAXD SEA OF JAPAN. 405 



CRANGON, Fabr. 



Crangon CONSOBRINUS, de Man. (P). 31. figs. 16-19.) 



Crangon consobrinws, de Man, in Ann. & Mag. Nat. Hist. ser. 7, vol. xvii. 1906, p. 401. 

 Crangon affinis, Ortmann, in Spengel, Zool. Jahrb., Syst. v. 1890, p. 531. 



One adult egg-laden female from the Inland Sea of Japan, caught in deep water. 

 This species is closely allied to Crangon alaskensis, Lockington, from Mutiny Bay, 

 Alaska*, but as it is perhaps different, I think it well to publish a somewhat detailed 

 description. 



Measured in the middle line, this specimen appears to be 48 mm. long, from tip of 

 rostrum to the end of the telson ; the carapace, inclusive of the rostrum, measures 

 llf mm., i. e. one-fourth of the whole length, without the rostrum it is 10 mm. long. 



The rostrum is distinctly shorter than the eye-peduncles when they are directed 

 straight forward, and reaches only to Ihe corneas; it is rather narrow, spatulate, the 

 sides nearly parallel for a portion of their length, though the rostrum is very slightly 

 narrowed behind the middle ; the edges are somewhat upturned and the sides curve 

 anteriorly to the rather acute tip. The carapace is pubescent on each side, but glabrous 

 posteriorly and in the middle of the dorsal surface, but tlie short hairs are here perhaps 

 partially worn off. The single median gastric spine, which is of usual size and slightly 

 directed upward, is situated at one-fourth the length of the carapace from the tip of the 

 I'ostrum, the distance betAveen both tips being 3 mm. On each side is the hepatic 

 spine, which has the same size as the gastric, and the three spines are situated in a 

 transverse line. In its general shape the abdomen resembles that of Crangon vulgaris : 

 it is three times as long as the carapace (rostrum included). The first, the second, and the 

 third segments are rounded above; the third, however, shows a slight depression on each 

 side of the median line just behind the middle. The fourth segment presents a trace of 

 carinatlon along a very short space on the posterior half; the faint and obtuse carina does 

 not, however, reach either to the middle of the segment or to its posterior margin. The 

 fflh segment is distinctly carinate ; the rather obtuse carina arises about at one-sixth the 

 length of this segment from its anterior cxtremi'y and terminates quite near tlie posterior 

 margin. The sixth segment, which is 7 mm. long, resembles that of Crangon vulgaris, but 

 its upper border has a shallow median groove ; as in Crangon vulgaris, the; sixth segment is 

 sulcate beneath, the furrow is rather shalloAV, and, as in that species, there is a sharp tooth 

 at the posterior end between the bases of the uropods. The telson is 10 mm. long, almost 

 once and a half as long as the sixth segment and just as long as the carapace (rostrum 

 excluded) ; the slender and gradually tapering telson, which is faint Ig grooved above, 

 terminates in a sharp tooth, on each side of which three movable spinules are inserted ; 

 the second is the longest of all, twice as long as the others, and extends, like the third, 

 a little beyond the extremity of the telson. The inner caudal swimmerets are just as 

 long as the telson, the outer are very little shorter. 



The eye-peduncles (PI. 31. fig, 16) resemble those of Crangon vulgaris. The antennular 

 peduncles reach just beyond tlie middle of the distance between the orbital margin of the 



* Rathbun, 'Decapod Crustaceans of the North-west Coast of North America,' 1904, p. 114. 



58* 



