154 PYRAMlDELLIDiE. 



also be referred to the same category of probable syno- 

 nyms. The variety terebellum agrees with Requien^s too 

 succinct notice of Chemnitzia per kit a. 



24. O. spiRALis^j Montagu. 



Tiirho spiralis, Mont. Test. Br. (ii.) p. 323, t. 12. f. 9. 0. spiralis, F. 

 & H. iii. p. 299, pi. xcvii. f. 2, and (animal) pi. FF. f. 8, 9. 



BoBY clear white, delicately suffused with snow-white points 

 of different sizes [white (Loven), sulphur-yellow (F. & H.)] : 

 snout of moderate length [narrow and entire (Loven)], flattened, 

 and rounded in front, extending from the tentacular membrane 

 beyond the foot : tentacles united at the base in front and widely 

 diverging, short, flat and broad, '' setose " [?], with a snow- 

 white line from base to point and a round flake-white dot at 

 each of their tips : eyes large and black [near each other (Lo- 

 ven)], placed behind the fork of the tentacles, on their internal 

 angles : foot rather broad, slightly auricled, and sinuated on 

 each side ; sole slightly grooved lengthwise in the middle 

 [notched in front (Loven)] ; tail rounded when the animal is at 

 rest or at half stretch, and bluntly pointed in full march. 

 (Clark.) 



Shell conic-oval, inchning to oblong, with a wide base 

 which is somewhat angulated, rather solid, semitransparent 

 and glossy : sculpture, numerous strong and straijjht or slightly 

 curved longitudinal ribs, broader than the interstices, about 30 

 on the body-whorl ; they are cut off at the periphery by the 

 first of a series of spiral stria} that revolve round the base and 

 are in number from 6 to 8 ; these striie are often closely pimc- 

 tured, owing to a decussation in that part by longitudinal 

 ribs which have otherwise disappeared, and they become less 

 distinct as they approach the base ; the apex of the shell is 

 quite smooth : colour white : spire pyramidal, and ending in a 

 blunt point ; nucleus obliquely twisted inwards : whorls 5-Q, 

 convex but flattened, rapidly enlarging, and abruptly shelving 

 towards the suture ; the last occupies about three-fifths of the 

 shell : suture narrow and deeply excavated, nearly straight : 

 mouth irregularly rhomboidal, forming an acute angle above 

 and considerably expanded below ; its length equals two-fifths 

 of the whole spire : outer Up sinuous, contracted on the upper 

 part, sloping upwards to the under side of the periphery : inner 



* Wi-eathed. 



