158 PROCEEDINGS OF THE ACADEMY OP 



spine of the other segments, though not quite so large. Telson bifid, ^he 

 forks rather elongated. Color of the alcoholic specimens greenish-grey, 

 mottled with paler and darker patches. Length about two-fifths of an inch. 



Although we have not seen the posterior pair of caudal stylets in this spe- 

 cies, which are lost in both our specimens, we have little doubt that it is 

 closely allied to G. longicauda Brandt, which inhabits the Asiatic coast of 

 the North Pacific, in which these stylets are very long. It differs from the 

 Asiatic species in having a spine at the extremity of the palm in the greater 

 gnathopod, in the shorter terminal joint of the peduncle of the superior an- 

 tennae, in the basal spine of the inferior antennas, and in the arrangement of 

 the dorsal spines of the abdomen. 



This species inhabits the circumlittoral zone. 



AMPHITHOJJOTUS 6EPTEMDENTATUS. 



Strongly compressed and carinated, like A. carinata ; carina dentated pos- 

 teriorly, the last two thoracic, and first five abdominal segments terminating 

 posteriorly in teeth ; last two teeth very much projecting and sharp. Head 

 with a deep notch or sinus on the front margin, near the inferior angle, at 

 the insertion of the inferior antennae. Rostrum rather slender, sharp, a 

 little curving downward, and reaching to a little beyond the middle of the 

 first joint of the superior antennae. Eye moderately large, oval, and oblique 

 in position. Antennae about one-third as long as the body ; the superior 

 ones with flagellum of eleven joints ; inferior ones about as long as the su- 

 perior, with a forward-pointing spine at the base below, and a seven-jointed 

 flagellum. 



Gnathopoda with small but well-formed subcheliform hands ; remaining 

 feet as usual in A. carinatus and the other species of the group. Length half 

 an inch. 



Found at and below low-water mark. 



Amphithoxotus occidentalis. 



Closely allied to the arctic A.panopla Kr., and the east-coast species, A. 

 cataphractus Stm., but differing from both in being more elongated, having 

 less height and breadth. It also differs from the latter species in being less 

 strongly carinated and dentated ; but the carinas are sharper than in A. pan- 

 opla, and the two teeth on the second abdominal segment are especially 

 prominent. The integuments are rather less indurated than in the allied 

 species. The superior antennas are a little longer than the inferior, but 

 scarcely more than one-fourth as long as the body. 



Length from tip of rostrum to tip of telson, 0-76 ; greatest breadth, 0-21 : 

 height, 0-24 inch. 



Two specimens were brought home by the Boundary Commission. 



Ampelisca pugetica. 



Head not much produced. Antennae of both pairs very slender ; superior 

 ones less than half as long as the inferior ones, with the basal joint very 

 thick, twice as thick, though only half as long, as the next joint. Superior 

 antennae four-fifths as long as the body ; peduncle long, smooth above. 

 Dorsum of the thorax and abdomen for the most part smooth and rounded, 

 but the last three joints of the abdomen are separated from the preceding 

 ones by a deep notch, and project into two sharp teeth. Terminal joint 

 in the third and fourth pairs of feet, one-half longer than the two preceding 

 joints together. In the seventh pair of feet the meros-joint is expanded pos- 

 teriorly into an ovate lamina, fringed with plumose setae, as in A. laevigata. 

 Posterior margin of the third abdominal segment with a small notch just 

 above the inferior angle. Last pair of caudal stylets large, with rami much 



[June, 



