REPOET ON THE AMPHIPODA. 30S' 



1857. Stimpson, William. 



The Crustacea and Echinodermata of the Pacific Shores of North America. 

 [Extracted from the Journal of the Boston Society of Natural History, Vol. VI.] 

 Riverside, Cambridge. 1857. 92 pages. PI. xviii.-xxiii. Amphipoda, pp. 73-82. 



Gaprella califomica is accepted somewhat doubtfully by Boeck. Mayer, without definitely 

 uniting Boeck's species with Stimpson's, refers each to ft linearis L. CoropJiium spiniccrne, 

 Stimpson, was apparently unknown to Spence Bate, as in the Brit. Mus. Catal. he makes a 

 new Corophium spinicorne, which Boeck identifies with Corophium crassicorne, Bruzelius. 

 CoropJiium sabnonis, which Stimpson took, " not in a very good state of preservation," out 

 of the stomach of a salmon, had almost better have been left there, instead of being drawn 

 forth to create a very indistinct species. Erichthonius rapax, n. s., here described, is rede- 

 scribed by Boeck in his Californian Amphipod-fauna, and transferred to the genus Gerapus, 

 but if S. I. Smith's definition of the latter genus be accepted, Stimpson's nsnae Uriel/ tJi on his 

 rapax must be restored, "as the second uropods are biramous. Orchestia scahripes, Dana, is here 

 referred to Megalorchestia, Brandt, which is superseded by the earlier OrcTiestoidea, Nicolet, 

 Megalorchestia california7ia, Brandt, is here distinguished from Megalorchestia scahripes, 

 in common with which it is referred to the genus Orchesfoidea in the Brit. Mus. Catal. 

 Orchestia californiensis, Dana, 1854 [1856], is here mentioned, a species which does not 

 appear in the Brit. Mus. Catal. Orchestia trasldana is described, and distinguished from two 

 closely allied species, Orchestia pugettensis, and Orchestia piclceringii, Dana. AUorcliestea 

 seminuda is described and distinguished by minute characters from Allorchestes pugettensis, 

 Dana. Allorchestes plumidosus, n. s., is distinguished from Allorchestes semhmda by characters 

 doubtfully of specific value. Both species are described as common at San Francisco. 

 Dana's species Allorchestes angustus, Gammarus pugettensis, and Iphimedia pugettensis, and 

 Brandt's Gammarus sitchensis and Gammarus atchensis are recorded. Mcera confervicola, 

 Stimpson, is renamed Gammarus conferviaolus. It " differs from G. Atchensis in the 

 smoothness of the dorsal surface of the first three abdominal segments." The last 

 species described is Phoxus grandis, n. s. Like several others from this paper, it is not 

 recorded in the Brit. Mus. Catalogue. The description is as follows : — " This species is of 

 a much larger size than is usual in the genus. Body broad and robust. Rostrum lamelli- 

 form, expanded over the bases of the superior anteuuse, with a broadly rounded extremity. 

 Superior antennae bi-flagellate, the inner flageUa very little smaller than the outer ones ; 

 both 12-articulate ; penultimate article of peduncle entirely concealed beneath the rostrum. 

 Inferior antennae a little longer than the superior ones ; terminal article of peduncle broad 

 at its extremity where its outer angle is produced and rounded ; its inner angle bearing the 

 1 5-articulate flagellum. Eye transversely oblong. Feet covered with simple hairs. Those 

 of the first and second pairs with small subcheliform hands ; those of the third and fourth 

 pairs with the third and fourth articles dilated, the fifth slender, the sixth very small. 

 Feet of the posterior three pairs very much widened ; those of the sixth pair largest. Caudal 

 stylets of the first and second pairs with short styliform rami, the inner ones being a little 

 shorter than the outer ones ; those of the third pair with long, flattened, equal rami, the 

 outer ones spinulose along their outer edges, both fringed with long setre on the innei' 

 sides. Terminal caudal spines of considerable length. The color is yellowish-white. 

 Length, half an inch. It was dredged on a sandy bottom in ten fathoms, in the channel 

 near the entrance of San Francisco Bay." 



