78 BULLETIN 138, UNITED STATES NATIONAL MUSEUM 



over half length of ischium measured on inner edge. Chelipeds 

 stout; fingers slender, curved, prehensile edges denticulate. 

 Oligocene; Miocene; Recent. 



PERSEPHONA BIGRANULATA, new species 

 Plate 11, figs. .^8 



Descri'ption. — Carapace (pi. 11, fig. 6), excluding front and spines, 

 almost circular ; the three j^osterior spines are broken off near the base, 

 two are at the ends of the posterior margin, the median spine well above 

 that margin (pi. 11, fig. 8). The surface is covered with two sorts 

 of granules, (1) bead granules-^ of small size but still visible to 

 the unaided eye and present everywhere except on the slope of the 

 front and orbits and in the branchio-hepatic hollow and (2) very 

 minute granules filling all the interspaces but not touching one 

 another. Regions not well defined. Hepatic region slightly elevated. 

 Front broadly bidentate, prominent dorsally, not so advanced as to 

 conceal the ends of the branchial channels. The upper part of the 

 front is granulate. Orbits round; two closed fissures in upper 

 surface, a deep smooth gutter on outer surface; otherwise the outer 

 surface of the orbit as well as of the projecting and obscurely-facet- 

 ted side-wail of the hepatic region is coarsely granulate, and has 

 no well defined marginal line. At the base of the front, between it 

 and the gastric region there is on either side a shallow hollow, and 

 another exists opposite the constriction between hepatic and branchial 

 regions. The margin of the branchial region (pi. 11, fig. 7) is 

 marked by a rim of bead granules considerably larger than those 

 of the dorsal surface. The intestinal region is dimly outlined later- 

 ally at least by a curved, shallow, impressed line which ends out- 

 side of, and before it reaches, the lateral spine. The surface about 

 the spines and on the posterior margin is coarsely and densely granu- 

 late without forming a marginal line. The lower surface of the 

 carapace is densely but finely granulate, a large hollow is beneath 

 the lateral constriction. 



Sternum (pi. 11, fig. 5) densely granulate and very coarsely so 

 at base of chelipeds ; first, second, third, and base of fourth segment 

 of abdomen granulate; remainder of abdomen smooth. The ab- 

 domen indicates maturity; it is filled with oblong concretions re- 

 sembling superficially foraminifera. They are probably formed 

 about masses of the minute eggs common to this genus. Chelipeds 

 and legs are wanting and the maxillipeds cannot be made out. 



Measurements. — Female holotype, length of carapace exclusive of 

 spine 23.2 mm., width of same 20.7 mm., fronto-orbital width 4.7 

 mm., width of intestinal region 9.1 mm. 



" Many of these granules are elongated apparently by a deposit of mud small particles 

 of which have perhaps been swept against them and adhered to their anterior side. The 

 granules thus affected are chiefly on the right side of the carapace. 



