INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 561 



pair. The ultimate pair very long and armed with fascicles of spines 

 along the margins. Divisions of the telson slender, spinous at the tips. 



In life dark greenish slate-color, changing in alcohol to dark slate. 



Length, 7-9 mm . 



New Jersey to Cape Cod. 



Ampelisca. Plate IV, tig. 17. (pp. 431, 507.) 



The species of this genus found upon our coast have not yet been 

 carefully studied. At least two species were taken in Vineyard Sound 

 and Buzzard's Bay. The genus is readily recognized, but the species 

 are difficult to distinguish. 



Byblts serrata Smith, sp. nov. (p. 501.) 



Female : Dorsum rounded above, with no trace of a longitudinal carina 

 upon the abdomen j third segment of the abdomen broadly rounded at 

 the postero-lateral angle. Antennula about as long as the peduncle of 

 the antenna ; fourth segment of the peduncle of the antenna longer than 

 the fifth. Inferior margins of the epimera of the first and second pairs of 

 legs serrate, with slender and acute teeth alternating with the marginal 

 cilia ; carpus in the first pair scarcely if any longer than the propodus ; 

 carpus in the second pair very much longer than the propodus. In the 

 third and fourth pairs of legs the dactylus as lou g as the propodus. Basal 

 segment in the seventh pair of legs expanding distally, the posterior 

 margin nearly straight, the anterior and inferior margins evenly arcuated, 

 and reaching as far as the distal end of the carpus; carpus about as long- 

 as, the ischium and merus together, a little less than twice as long as 

 broad, and armed with long spines upon the anterior and distal margins, 

 but the posterior margin wholly unarmed ; propodus almost as long as 

 the carpus, and nearly four times as long as broad, anterior margin un- 

 armed, the posterior armed upon the outside with two transverse rows 

 of three or four spines, decreasing in size as they recede from the mar- 

 gin, the distal end with a spine each side the slender dactylus. Baini 

 of the first pair of caudal stylets equal, as long as the base; outer rami 

 of the second pair shorter than the inner; rami of the posterior pair 

 equal, longer than the bases, reaching to the tips of tke rami of the first 

 pair. Telson as long as the breadth at base, cleft rather more than half 

 its length, the lateral margins arcuate, and rapidly converging toward 

 the evenly rounded extremity. 



Alcoholic specimens are pale yellowish, the epimera, bases of the pos- 

 terior legs, and the sides of the abdomen specked and mottled with 

 numerous points of dark pigment crowded irregularly together. 



Length, 10-12 mm . 



Deep water off Vineyard Sound and Buzzard's Bay. 



Ptilocheirus pinguis Stimpson. (p. 431.) 



Marine Invertebrata of Grand Mauan, p. 56, 1853. Proiomedia pingus Bate, 

 Catalogue Ampliip. Crust. Brit. Mus., p. 170, PI. 31, fig. 3, 1863. 



Common on the whole coast of New England upon muddy bottoms 



S. Mis. 01 — -3G 



