352 AMPITirODA ABEURANTIA. 



2. Protella gracilis. (rr.A-ri; LV, fig. 5.) 

 Protella gracilis, Dana, U. S. Explor. Exped p. 812. pi. 54. f. 2. 



"Male. — liody slender, ^vithout spines or tubercles, front obtuse. 



• First segment of the pereion a little longer than the cephalon ; 

 second, thii'd, fourth and fifth segments subequal, rather oblong. 

 8up{?rior antenna; V(^ry slender, longer than the body ; peduncle 

 but Httle shorter than the body ; second and third joints of the 

 peduncle subequal ; tiagellum more than once and a half the length 

 of the preceding joint. Propodos of the first pair of gnathopoda 

 very small, caqius not shorter : propodos of the second pair four 

 times as long as that of the first pair, rather narrow ; palm nearly 

 naked, armed \v\W\ three teeth, one external, one internal, and one 

 subapical, truncate and oblique. IlucUmcntary feet slender and 

 styliform, a little shorter than the segments. Branchiae narrow, 

 subelliptic. 



" Female. — Propodos of the second pair of gnathopoda hardly broader 

 than in the male ; palm arcuate, sjDiniilose, short, three-toothed, 

 one exterior, acute, and two acute, very short subapical teeth. 



" Length iths of an inch. 



" Hah. From thirty-one fathoms water, in Balabac Passage, at- 

 tached to a Plumularia and a Gorgonia." — Dana. 



3. CERCOPS. 



Cercops, Kroyer, Nat. Tidshr. iv. p. 496, 1843. 



Body cylindiical. Cephalon confluent with the fii'st segment of the 

 pereion. Pleon rudimentary. Gnathopoda subchelate ; branchiae 

 attached to the second pair. First two pairs of pereiopoda obsolete ; 

 branchite attached to the corresponding segments. Fifth and sixth 

 pairs of pleopoda developed, biarticulate, biramose, styliform in 

 the male ; rest obsolete. 



1. Cercops Holbolli. (Plate LV. fig. 6.) 

 Cercops Holbolli, Kroyer, Nat. Tklsh: iv. p. 496, 184-3. 

 Cephalon surmounted by a strong anteriorly- directed tooth, and a 

 small one on each side, anterior to the eyes. Pleon consisting of 

 five or six cylindrical segments. Antenna) short ; inferior shorter 

 than the superior. Second pair of gnathopoda larger than the first ; 

 propodos ovate, slightly tapering anteriorly ; palm convex, armed 

 with a small tooth, and defined by a sharp process. Pleopoda on 

 the antepenultimate and penultimate segments biramose; rami 

 styliform. 

 Hah. Arctic Sea ? {Holholl). 



