REPORT ON THE CRUSTACEA MACRURA. 485 



The dorsal surface is armed with a sharp tooth on the gastric region and another on 

 the hepatic region, on each side in the same line, corresponding with the anterior 

 extremity of the branchial region. 



The pleon is about twice the length of the carapace ; the somites gradually 

 increase in length posteriorly, and also become laterally more compressed, particularly 

 from the third somite to the sixth, which is flattened on each side. These somites show 

 a slio-ht tendency to a central elevation , which is not apparent until the specimen is dry ; 

 it is faintly visible on the third somite, slightly more defined on the fourth, but on the 

 fifth the median line is depressed, while a slight elevation exists on each side. This 

 central depression is repeated on the dorsal surface of the telson, which is narrow and a 

 little longer than the sixth somite, reaches a little beyond the extremity of the lateral 

 plates of the rhipidura, terminates in a sharp point, and is armed on each side with three 

 spines distantly separated. 



The appendages correspond closely with the European Crangon vulgaris. 



Habitat.— Station 233, May 17, 1875; lat. 34° 39' N., long. 135° 14' E.; Bay of 

 Kobe, Japan ; depth, 8 fathoms ; bottom, mud. Eight females. Dredged. 



Station 233a, May 19, 1875; lat, 34° 38' N., long. 135° 1' E.; off Japan; depth, 

 50 fathoms ; bottom, sand. Four specimens, females. Dredged. 



Station 233b, May 26, 1875 ; lat. 34° 18' N., long. 133° 35' E.; off Japan ; depth, 15 

 fathoms ; bottom, blue mud. Three females and one male (?) with Bopyrus. Trawled. 



Three of the specimens which have been brought from the last locality are 

 females bearing many ova ; the fourth is small and slender, and has been attacked by a 

 species of Bopyrus. 



The only differences that I can recognise between the British Crangon vulgaris and 

 these specimens of Crangon affinis, are that the latter genus has the rostrum and 

 ophthalmopoda a trifle longer, the ventral tooth between the second pair of pereiopoda 

 more slender and perpendicular, and that the posterior somites of the pleon exhibit traces 

 of an elevation in the median line, but certainly not worthy of being called a carina ; a 

 depression also exists in the same position on the sixth somite as well as on the telson. 



In the typical specimen of Crangon vulgaris, the dorsal surfaces of the last somites of 

 the pleon and the telson are smooth and rounded, but there is a certain average number 

 in which there is an indication of a slight dorsal depression in the median line of the 

 sixth somite and at the anterior extremity of the telson, which latter is a little shorter 

 than the. lateral caudal plates in the typical British species, but reaches a little beyond 

 them, and is also a little slighter in the Japanese Crangon affinis. 



Stimpson obtained some specimens, which he named Crangon. propinquus, from the 

 northern coast of Japan. They were taken on a muddy and sandy bottom, at a depth 

 of from 4 to 20 fathoms. These he describes as closely approximating to Crangon vulgaris, 



