G96 EEV. K. Booa watson on the 



minute rounded embryonic 1| whorl scarcely rising above the 

 level. WJiorls 6, of rather rapid increase, with a narrow flat 

 shelf below the suture, thence sloping flatly to the shoulder- 

 carina, from which point the contour-line descends perpendicu- 

 larly ; the base is inflated at the edge and flattened in the middle. 

 Suture deeply impressed between the narrow flat shelf below and 

 the overhanging carina above. Mouth slightly oblique, but with 

 a perpendicular pillar, round ; nacreous within. Oioter lip thin, 

 transparently porcellanous on the edge, but thickened by nacre 

 within. Fillar-lip perpendicular, rounded within the moutb, 

 advancing to a sharp point in front, slightly reverted but not 

 appressed, having a small open furrow and a minute umbilical 

 chink behind it. H. 0-3. B. 0'26, least 0-22. Penultimate 

 whorl 0-053. Mouth, height 0-14, breadth 014. 



This species extremely resembles T. occidentalis, Migh., but is 

 smaller, is broader in proportion, with a less high spire; the 

 apex is not sharp and projecting, but flattened down and rounded : 

 the whorls are much more scalar, and of more rapid increase ; 

 the base is more tumid on its outer edge and more rounded. 

 The apex is ornamented with a minute 

 and quite irregular inlaid work of an- 

 gular depressions, parted by very nar- 

 row interruj^ted raised lines ; whereas in 

 that species the ornamentation is like Ornamentation of apex. 



honeycomb, with relatively large, nearly T. occiden- T. stiro- 

 11 1 -J, J • -t n J talis. phones, 



regular hexagonal pits and raised flat ^ 



borders. This diff"erence is shown in the woodcut. The threads 

 on the base are approximate, not parted in the middle by a 

 smooth zone, and the pillar-lip is not appressed as in that spe- 

 cies ; the outer lip, too, is thickened within by the layer of nacre. 



3. Trochus (Ziziphinus) tiaka, W. (From its high narrow 

 form.) 



St. 24. Mar. 25, 1873. Culebra, St. Thomas, Danish "West Indies. 

 390 fms. Mud. 1 full-grown and 8 young specimens. 



St. 56. May 29, 1873. Bermudas. 1075 fms. G-rey ooze. 3 

 specimens. 



Shell. — Small, conical, high-spired, flatly rounded on the base, 

 sculptured, w^hite, dull on the surface, with a bright nacreous 

 gleam shining through. Scidpture. Spirals — on the upper part of 

 the last whorl there are two rows of tubercles, the first aud 



