TROM THE INLAND SEA OF JAPAN. 407 



related to Craiigon alba, Holmes, and Crangon liolmesl, E-atbb., from the North-west 

 coast of North America. From the former it differs, however, at first sight by the blad<^ 

 of the antenual scale which agrees with that of Gnmgon vulgaris ; from the latter also 

 by the antennal scale, which measures only two-thirds the length of the carapace, 

 exclusive of the rostrum, while the blade appears, moreover, broader at the extremity 

 than that of Crangon holmesi. 



The two specimens are nearly of the same size : they are 46'5 mm. and 44 mm. long 

 from tip of rostrum to the end of the telson. In the larger specimen the carapace 

 is 12-5 mm. long, rostrum included, and 11 mm. without it; in the other it is 11*75 mm. 

 long, rostrum included, and 10"5 mm. without it, so that the carapace, rostrum included, 

 is a little longer than one-third the abdomen. 



Viewed from above this species closely resembles Crangon vulgaris, but the numerous 

 small, dark spots with which carapace and abdomen of the common shrimp are mottled 

 are almost wanting in Crangon cassiope. Small violet spots are, however, seen on 

 the peduncle and inner flagellum of the inner antennae, on the antennal scales, on the 

 hepatic region of the carapace between the pterygostomian and hepatic spines, near tlie 

 posterior margin of the carapace, on the telson and on the uropods. 



Even on close inspection the carapace shows no differences from that of Crangon 

 vulgaris. The narrow, triangular rostrmn is as short in proportion to the eye-peduncles 

 as in that species, the gastric and the two hepatic spines agree also in both. The 

 abdomen, viewed from above, also closely agrees with that of Crangon rulgaris; all 

 the seven segments are rounded above, but neither the sixth nor the seventh shows ai/i/ 

 tendency to become flattened or grooved, as is sometimes the case in Crangon vulgaris. 

 In the common shrimp the ventral surface of the sixth segment is marked by a 

 moderately deep groove, which usually begins near the anterior margin and more or less 

 gradually widens posteriorly ; on the posterior end is a sharp spine, which is directed back- 

 ward. In Crangon cassiope, however, the ventral surface appears in the middle of the 

 segment rounded and convex, but the posterior fourth is slightly concave, and there is also 

 a short, transverse, though quite shallow pit or depression at one-third of the segment 

 from its anterior margin ; instead of a sharp spine one sees in Crangon cassiope, at 

 the posterior end, a subacute conical tubercle. On each side of the middle line the 

 ventral surface is punctate; one observes numerous large puncta and between tliem 

 many others that are quite minute. The two pairs of antcnnte closely resemble 

 those of Crangon vulgaris. The antenual scales (PI. 32. fig. 20) measure along their 

 outer margin two-thirds the length of the carapace without the rostrum, and they ai(> 

 two and half times as long as broad; the end of the blade (fig. 21) is slightly rounded, 

 makes a distinct angle with the inner margin, and is four times as broad as the adjacent 

 part of the spine, which reaches considerably beyond it. The antennal scales closely 

 resemble those of Crangon vulgaris and the outer antennse are just as long as the body. 

 As regards tlie inner antenna?, I wish only to observe that the stylocerite is a little shorter 

 than the first joint of the peduncle, and that these antenna? otherwise fully agree with 

 those of the common European shrimp. 



The external maxillipeds, which reach to the end of the antennal scales, do not fully 



