MUSEUM OF COMPARATIVE ZOOLOGY 275 



Solarium peracutum n. s. 



Plate XXXIII. Figs. 2, 5. 



Shell whitish or yellowish, thin, very depressed, conic, extremely sharply 

 keeled at the periphery; sculpture faint, base rounded, excavated just within 

 the periphery; umbilicus large, scalar, the walls in each whorl deeply concave, 

 bordered below by a very strong nodulous rib, terminating in a sulcus at the 

 base of the columella. Nucleus sinistral, immersed, whorls six or seven without 

 the nucleus; sculpture above consisting of numerous radiating somewhat flexu- 

 ous fine incremental lines crossed at the periphery by one strong flattened spiral 

 thread, nodulous on the earlier whorls and articulated faintly with yellowish 

 brown. Inside this is a much finer simple spiral, and within this again another 

 large one, also nodulous on the early whorls. Hence to the suture are four or 

 five smaller flattened spirals, uniform, but fainter on the later whorls and sepa- 

 rated by somewhat wider faintly but distinctly channelled interspaces. Periph- 

 ery of the shell brought to a thin but rounded carinal edge, which is however 

 about the sharpest of any known in the genus. Base sculptured by numerous 

 fine spirals, by strong but irregular radiations from the umbilical margin, which 

 is marked on its edg% vith about 22 strong nodules, and bordered by two grooves 

 enclosing a wider subnodulous spiral space, becoming less marked with age. 

 Columella short, thickened, with a sulcus at its base; basal margin thickened 

 near the sulcus ; the remainder of the apertural margin thin and sharp, the 

 aperture itself almost triangular. Max. diameter of shell, 17.5; min. diam., 

 15.0; altitude, 6.0 mm. 



Habitat. Barbados, 100 fms.; Station 290, off Barbados, in 73 fms., coral 

 and shell, bottom temperature about 71°.0 F. ; Station 128, off Frederikstadt, 

 in 180 fms., gray ooze, bottom temperature about 60°.0 F. 



This species does not much resemble any of the living forms. It is most 

 like S. hcmisphericuvi Seguenza, a fossil from the Tertiaries of Messina. This 

 has the same form, except that it is sub-excavated above near the periphery as 

 well as below. The details of sculpture differ considerably, but the incon- 

 spicuous character and slight prominence of the sculpture is much the same in 

 both. The fossil has a much smaller umbilicus, and the rib about it is feebly 

 marked, though the edge is nodulous. 



Solarium Sigsbeei n. s. 



Plate XXIII. Figs. 3, 3 a. 



This shell was supposed at first to be the young of S. peracutum; further 

 study and comparison with young specimens of the same size show that, though 

 related, they are not identical. The sculpture is much more prominent and 

 granular, the whorls are more elevated and much less discoid. The details of 

 sculpture are also quite different, as will be seen by the figure. The color is 

 pale yellowish or waxen. Max. diameter of the shell figured, 5.5 mm.; alti- 

 tude, 2.3 mm. 



