36 BULLETIN (J.S, UNITED STATES NATIONAL MUSEUM. 



TURBONILLA (CHEMNITZIA) MURICATA Carpenter 



Plate 2, fig. 9. 

 Chemnitzia murimta Cakpentek, Cat. Maz. Shell, 1856, p. 428. 



Shell elongate-conic, milk-white. Nuclear whorls three, forming 

 an elevated helicoid spire, whose axis is at right angles to that of the 

 succeeding turns, in the first of which it is almost half immersed. 

 Post-nuclear whorls moderately rounded, somewhat contracted at 

 the suture, strongl}^ shouldered at the summit, marked by very 

 strong, slightly protractive axial ribs, of which 14 occur upon the 

 first to fourth ami 16 upon the remaining turns. These ribs extend 

 prondnently to the summit which they render muricated. Inter- 

 costal spaces as wide as the ribs, deeply impressed, terminating at 

 the periphery. wSutures very strongly marked. Periphery and base 

 of the last whorl well rounded, smooth. Aperture rhomboidal; 

 posterior angle obtuse; outer lip thin, showing the external sculpture 

 within; columella slender, slightly twisted and curved. 



The type and four specimens were taken from Spondylus at Mazat- 

 lan, Mexico. The type and one other specimen are on tablet 1993, 

 Liverpool collection, British Museum. It has seven post-nuclear 

 whorls and measures: Length 2.3 mm., diameter 0.7 mm. 



This shell, as far as the structure of the spire is concerned, stiangely 

 recalls Turhonilla {Afimunda) turrita of C. B. Adams. The base, 

 however, is entirely different. 



TURBONILLA (CHEMNITZIA) SANTAROSANA, new species. 



Plate 2, figs. 7, 7a. 



vShell small, delicate, subdiaphanous to milk-white. Nuclear 

 whorls two and one-half, forming a moderately elevated helicoid 

 spire, the axis of which is at right angles to that of the succeeding 

 turns, in the first of which it is very slightly immersed. Post-nuclear 

 whorls well rounded, slopingly shouldered near the summit, slightly 

 constricted at the suture, marked by broad, low, rounded, axial ribs, 

 which become somewhat flattened at the summit. Of these 16 occur 

 upon the first to fourth, 18 upon the fifth and sixth, while upon the 

 penultimate they are veiy much enfeebled and ill-defined. Inter- 

 costal spaces narrow, shallow, the depressed area terminating a 

 little posterior to the suture. Sutures constricted. Periphery and 

 base of the last whorl somewhat inflated. Aperture moderately 

 large, rhomboidal; posterior angle obtuse; outer lip thin, showing 

 the external sculpture within; columella very thin and strongly 

 curved. 



The type and five specimens (Cat. no. 163239, U.S.N.M.) were 

 dredged at U. S. Bureau of Fisheries station 2902, in 53 fathoms, 

 temperature 45°, off Santa Rosa Island, California. The type has 



