AMPHTPODA OF SOUTHERN NEW ENGLAND. 493 



Eusirus cuspidatus Kroyer. 



Head with ;i short, pointed rostrum, which is rounded above and curved downward; eyes reni- 

 forni. pale in alcoholic specimens; first antennae scarcely half length of body; second segment as long 

 as tirst and over twice the length of third; secondary flagellum minute, one-jointed; second antennae 

 nearly as long as first; last joint of peduncle nearly as long as preceding one; flagellum a little shorter 

 than peduncle; first four coxal plates of subequal depth, the first produced forward and rounded at 

 lower angle; second and third equal, twice as deep as wide, rounded below; fourth nearly as wide as 

 deep, deeply excavated at upper posterior angle; first and second gnathopoda subequal in size and 

 similar in form, carpus attached near middle of anterior margin of hand, a narrow process extending 

 down posterior margin half way to palm; palm long, evenly curved, defined posteriorly by a small 

 prominence; dactyl long, slender, fitting closely to palm; first and second peraeopods slender and 

 elongate; three posterior pairs increasing successively in length, pos- 

 terior margins of expanded basal joints serrate; last segment of 

 thorax and tirst two segments of abdomen with a median dorsal 

 spine at posterior end; the first tour segments of abdomen and to a 

 less extent the last segment of thorax with a median dorsal carina; 

 fourth segment with a marked depression above a little in front of 

 middle; postero-lateral angle of third segmentof abdomen produced 

 and acute; that of fourth segment broadly rounded and armed with 

 numerous upturned serrations; much less evident serrations on the Eusirus cuspidatus Uter Sara 



postero-lateral margins of first two segments; uropods extending 



backward to nearly the same point; peduncle of tirst pair with a large spine on outer side of distal 

 extremity; outer ramus relatively much shorter than inner in second uropods than in first or third; 

 telson long, narrow, flattened, grooved above, with a narrow fissure at posterior end which extends 

 nearly to middle. 



Length, 17 mm. 



Norway: Arctic regions; Greenland; Grand Manan. 



Rhachotropis aculeata (Lepechin). 



Head with a prominent, acuminate rostrum which is slightly curved downward; eyes prominent, 

 tenuid, their inner ends obtusely pointed; a rounded prominence between posterior ends of eyes; first 

 antenna nearly as long as second, first basal joint thick, flattened; third joint about one-third length 

 of second, which is shorter than first; flagellum subequal to base; thorax broad, last two segments 

 with three sjroiig spines on posterior margin, last segment considerably longer than preceding ones; 

 first five segments devoid of spines with exception sometimes of a trace of a spine on the mid-dorsal 

 line of fifth; coxal plates small, first strongly produced in front and incurved at its anterior angle; 

 fourth and fifth with a short longitudinal eminence on outer surface; first two gnathopods similar; 

 carpus short, with a narrow posterior lobe; hand large, ovate, a prominence at upper end of the evenly 

 convex palm; all of the peraeopods with slender, elongate, slightly-curved dactyls, basal joints of fourth 

 and fifth pairs with a large tooth on proximal portion of posterior margin; last peraeopods much longer 

 than others, basal joint much expanded proximally, the posterior margin strongly sinuous with a large 

 tooth at lower end; first three abdominal segments flattened at sides, with three longitudinal dorsal 

 carina?, each of which ends on the posterior margin of its segment in a spine, the middle carina having 

 a smaller spine near the middle of each segment; fourth segment with a median carina furnished with 

 two spines as in preceding segments, a small lateral carina on either side which bears no spine and 

 does not reach posterior margin of the segment; telson narrowdy triangular with a broad groove, 

 apex cut with a long narrow incision. 



Several specimens taken off the coast of New England measured from 20 to 28 mm. A large speci- 

 men from the Arctic < fcean received from Doctor Stebbing measured MS mm. This is one of the largest 

 of our species of amphipods, and is extensively distributed in the Antic regions. It is reported from 

 Labrador by Packard and Smith and by the latter also from northern New England. I have examined 

 specimens collected, off Cape Ann in 25 fathoms, which is as far south as I have any knowledge of its 

 occurrence. It is found in rather deep water. 



B. B. F. 1904—32 



