N0.1312. SYNOPSIS OF THE VENERIDJE^DALL. 405 



open; internal margins cronate, hing-o normal, teeth entire. Len^h, 

 1-i; height, 13; diameter, 8 mm. 



Collected by Arthur Schott, at Humboldt Bay, (lulf of Panama. 

 Cat. No. 6226, U.S.N.M. 



These specimens .are small, and very likeh' not of full sizi;; they 

 may also be somewhat bleached, but they certainly can not be identi- 

 fied with any of the other species of the coast. 



CHIONE (LIROPHORA) OBLITERATA, new species. 

 Plate XVI, fig. 2. 



Shell solid and heavy, subtrig'onal, with very po.sterior beaks; of a 

 pale yellow or 3'ellow-brown color, with faint purplish radial flames or 

 flecks; lunule short cordate, nearl}- smooth; escutcheon elongate, 

 excavated, smooth; beaks small, anteriorly directed; surface smooth 

 or obsoletely radially striated, sculptured with heavy tumid concentric 

 waves which in the adult become somewhat irregular and sometimes 

 coalescent on the disk, more or less angular and bifid on the posterior 

 dorsal slope; interior yellowish with a flush of purple near the hinge; 

 hinge normal; pallial sinus very short and small, angular, inner mar- 

 gins minutely crenate. Length, 24; height, 18; diameter, 14 mm. 



Humboldt Bay, Gulf of Panama, two left valves, Cat. No. 11(S21 

 and 6227 U.S.N.M. 



This is the analogue of the Atlantic O. latUlrata Conrad, but differs 

 by well-marked characters from that as Avell as from the species of the 

 pajpMa or inarise, type which have regular ribs. It reaches a length 

 of some 30 mm. 



CHIONE (TIMOCLEA) PERTINCTA, new species. 

 Plate XVI, fig. 9. 



Shell solid, ovate or cuneate, white externally, with a flush of pink 

 near the umbones, the small lanceolate lunule dark brown, the poste- 

 rior dorsal slope with wavy red-brown lines irregularl}?^ longitudinal. 

 There is a very narrow striated escutcheon ; beaks low, at the anterior 

 third; surface with feeble concentric sculpture not rising into lamella; 

 radial sculpture conspicuous, of sulci with the anterior slope steep and 

 short, the other covering the whole interspace to the next posterior 

 sulcus; near the lunule the sulci are close and well marked, then for a 

 short space they are almost absent, after which they extend with rather 

 wide interspaces to the posterior end of the shell; these characters of 

 the sculpture may not be invariable, but in the two best preserved 

 valves are similar; interior with the hinge strong, the middle left car- 

 dinal bifid, the pallial sinus short, linguiform, the cavity of the valves 

 except near the beaks and margin stained with very dark purple, the 

 imier margins finel}'^ crenulate. Length, 37; height, 28; diameter, 

 19 mm. 



