422 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxv. 



sloping gently anteriorly, but quite rapidly posteriorly for a short 

 distance, then again produced so that the posterior end is almost 

 truncate, and thus forming a dorso-posterior angle; lower margin 

 essentially straight. 



Muscle impressions four, lying one above another in a straight 

 line. Just posterior to the muscle impressions are situated two large 

 conical protuberances or tubercles, so prominent as to at once 

 characterize the species. 



Seen from above (fig. 1), the shell is broadest in the middle, about 

 half as broad as long, rather sharply pointed anteriorly, more evenly 

 and broadly rounded posteriorly, and plainly showing the two large 

 protuberances of each side, situated just posterior to the widest part. 

 Surface of the shell sparsely covered with small papillar elevations: 

 the central area also, as seen from the side, with from 30 to 40 small 

 lucid spots. Shell grayish in color. Pore canals not as evident as in 

 most species of Cythere. 



First antenna (fig. 3) about as usual for the genus, the terminal 

 spine of the penultimate segment the largest, the seta proximal to 

 it spine-like, and about the same length, the next spine blunt and 

 shorter; the proximal seta slender, and not more than three-fourths 

 length of spine beside it. In Cythere amevlcana these proportions 

 are different, the proximal seta of the penultimate segment being 

 longer than the spine just distal to it. 



Second antenna stout and of the usual type. (fig. 4). Penultimate 

 segment of the mandibular palp widened just beyond the middle. 

 Feet slender and as usual with the genus. 



Collected, along with Cythere americana, from shallow tidal pools 

 near Brighton Beach, New York, June 6, 190(5. 



A very few of these forms could be obtained by repeated use of the 

 Birge net, not more than four to five specimens of each of the two 

 forms just described, from at least a dozen hauls of the net. 



They are poor swimmers, and were only with difficulty seen, as they 

 burrowed about in the slime and ooze when placed in shallow glass 

 vessels. 



Type.— Cat. No. 38348, U.S.N.M. 



3. Family CYPKIDINID.E. 



16. Genus CYLINDROLEBERIS Brady. 



Cypridina Authors, 18GS. 



Asterope Philippi, Arch. Naturg., 8 Jahrg. 1840, Pt. 1, p. 186. — Glaus, 

 Untersuch. zur Erforseh. tier genealog. grundlage des Crustaceensys- 

 tems, Wein, 1876, p. 94. — Sars, Arch. Math. Naturv., Christiania, XII, 

 issT, p. 11.— Mutxer, Zool. Jahrb., Abth. Syst., V, 1890, p. 239. 



Cylindroleberis Brady Intellectual Observer, London, XII, 1867, p. 127; 

 Trans. Linn. Soc. Lond.. XXVI. 1N6.S. p. 464. — Muller, Die Ostracoden 

 des Golfes von Xeapel, XXI, 1S94, p. 216. 







