500 BULLETIN OF THE BUREAU OF FISHERIES. 



tubercle, dentate primary and secondary cutting plates, and a spine row composed of five stout, irregu- 

 larly serrate spines; palp with third joint about three-fourths the length of second; last two joints 

 Btrongly setose on inner margin; lower lip with rather small inner lobes; first maxilla- with inner 

 plate narrow, furnished with three plumose setse —one at tip and two near distal end of ciliated inner 

 margin; palp two-jointed, distal extremity nearly transverse and armed with several strong spines 

 and seta'; maxillipeds with inner plates well developed, extending a little beyond first joint of palp, 

 distal end broadly rounded, furnished with several short plumose setse and three short stunt teeth 

 near the middle line; outer plate about equaling second joint of palp, furnished with a few odontoid 

 processes on distal part of inner margin and two or three stunt plumose set;e at distal end; terminal 

 joint of palp claw-like; first gnathopods consisting of rudiments of coxal plate and basal joint, former 

 very small, latter curved, distally rounded, and furnished with several curved seta 1 around tip; coxal 

 plates of three following appendages well developed and about as deep as their segments; first gnath- 

 opods rather slender; carpus with a large, triangular posterior lobe; hand with palm oblique, only 

 slightly curved and minutely denticulated; dactyl with four spinous projections on inner margin 

 behind tip; second perceopods with coxal plate broader than deep and deeply excavated at upper pos- 

 terior angle; the three posterior perseopods increasing successively in length, basal joints broad, last 

 pair considerably longer, than preceding; claws of all the pairs large, strongly curved, and having a 

 small seta near distal end of inner margin; the posterior margin of third abdominal segment with sev- 

 eral upturned teeth above the rounded postero-lateral angles; first two pairs of uropods with rami 

 styliform, outer ramus considerably shorter than inner; second uropods not extending nearly so far 

 backward as first or third; third uropods with rami flattened, lanceolate, over twice the length of 

 peduncle, margins of both armed with numerous short spines and plumose seta-; telson deeply cleft. 



Length, n mm. Type No. 29244, U. S. Nat. Mus. 



Several specimens were taken near Woods Hole during the summer of 1900. Some were dredged 

 by the Fish Hawk in about 25 fathoms, and others were obtained off Nobska, at a depth of about 6 

 fathoms. The body and coxal plates in the living specimens were marked with blue or purplish pig- 

 ment spots, formed by small clusters of hexagonal pigmented cells of the hypodermis. Sometimes 

 the blue or purple color of these spots is replaced by a reddish brown, ami in some specimens neither 

 kind of spots occurs. There are also branched pigment cells on the body and appendages, which are 

 dark in transmitted light, but silvery green in reflected light. The flagella' of both pairs of antennae 

 are blue or purplish and the peduncles may contain branched pigment cells. The eyes are brownish. 

 When placed in a dish of sea water the animals swim for only a short distance and then curl up and 



drop to the bottom. 



The genus liutiu was first established by Fritz Midler to contain a species found on the coast of 

 Brazil (See Ann. and Mag. Nat. Hist, (3), vol. 15, p. 271), pi. x, 1865). The genus has not, up to this 

 time, been met with north of the equator. It differs from all the other genera of the Gammaridea in 

 the rudimentary character of the first gnathopods which in both the type species, B. caiharinensis 

 and the present one, consist of only the coxal and basal joints. Our species agrees quite closely with 

 the one described by Muller, but has the coxal joint of the first gnathopods much smaller and fewer 

 tooth-like processes on the inner margin of the outer plates of the maxillipeds. As in catkarinensis, 

 the eyes are larger and the antennae longer in the male than in the female, and the first and second 

 perwopods are furnished with long plumose seta' only in the male sex. In one male specimen in my 

 collection the second antenna' exceed the length of the body. 



Gammarus locusta (Linnseus). 



Gammarus ornatus Edwards, Ann. Sci. Nat. t. xx, 1830, p. 367, pi. in, figs. l-io. 



Body rather slender and compressed; eyes elongated, reniform, nearly reaching anterior margin 

 of short lateral lobes of head; first antenna- a little longer and more slender than second and often 

 (generally in females i shorter than half the length of body, the first joint a little longer than the 

 second, which is twice the length of the third; secondary flagellum longer than second joint of 

 peduncle and about N-jointed; peduncle of second antenna- stout, the last two joints of subecpial length; 

 flagellum shorter than peduncle; first gnathopods of male with hand elongated I much longer than 

 carpus), tapering from near the base, posterior margin continuous with palm, which is somewhat 

 uneven, armed with a stout spine near the middle and a large spine with a row of several smallerones 

 above it at distal end; second gnathopods of male with hand much larger than in first, about twice 



