320 Mr. E. A. Smith on jive new 



Hob. 36° 47' S. lat., 55° 17' W. long., 28 fms. Off the 

 mouth of the Rio de la Plata. 



This is a dull unornamental species, and chiefly character- 

 ized by the convexity of the whorls, the depth of the suture, 

 and the feebleness of the sculpture. 



Trochus (Zizipliinus) Coppingeri. 



Shell thin, shortly conical, rather shining, and somewhat 

 iridescent, owing to the thinness of the calcareous layer above 

 the pearl, very pale olive on the body- whorl, becoming darker 

 on the upper volutions and reddish at the apex, ornamented 

 with a series of minute red dots at the upper part of the whorls, 

 just beneath the suture, and a second series on an angle at the 

 middle of them, with a third series around the periphery 

 of the last volution, and some rather larger spots around the 

 umbilical region. Whorls seven ; the first three or four some- 

 what convex, with three coarse spiral lira?. Antepenultimate 

 whorl flat, sloping above, with an acute angle a little above the 

 base, spirally lirated ; lirse little raised, with the exception of 

 that at the angle and one immediately beneath the suture, 

 which is very prettily beaded. Penultimate like the preceding, 

 but with the sculpture less pronounced and the angle nearer the 

 middle. Last whorl still more feebly sculptured, the beading- 

 having become obsolete. It is biangulated at the middle, and 

 the space between the two angles is flat, giving the shell a 

 very angular aspect. Base a little convex, concentrically 

 striated, white at the middle, with a conspicuous depression at 

 the umbilical region, which is surrounded by three or four 

 strong lira?. Lines of growth fine. Aperture oblique, irregu- 

 larly pentagonal, smooth, and beautifully pearly. Columella 

 arcuate above, obliquely straightish inferiorly. Height 13 

 millims., diam. max. 14, min. 12. 



Hob. 36° 47' S. lat., 55° 17' W. long., 28 fms. Off the 

 mouth of the Rio de la Plata. 



This beautiful shell is very distinct in form and character 

 from any other in the genus. 



Nucula Uruguay ensis. 



Shell ovate, somewhat ventricose, moderately thick, olive, 

 smooth, with fine concentric lines of growth, bluish white 

 within, not very iridescent except upon the muscular scars, 

 very inequilateral. Anterior end rounded, posterior obtusely 

 angulated. Front dorsal margin curved, not oblique near the 

 umbo ; posterior a little oblique, subperpendicular or almost at 

 right angles to the anterior slope ; lower or ventral edge regu- 

 larly arcuate, forming an obtuse angle at its junction with the 

 hinder dorsal margin, smooth within. Umbones rather pro- 

 minent and acute. Teeth long, acute, about twenty behind 

 the ligamental pit, and nine in front. Pit itself small, narrow, 



