MOLLTJSCA OP THE ' CHALLENGER ' EXPEDITION. 95 



Shell. — High, conical, tectiform, carinated, umbilicated, with a 

 flattish depressedly conical base. Sculpture. There are many 

 sinuous, rather remote, longitudinal puckerings, minute below the 

 suture ; then evanescent, but on the whole lower half of the 

 whorls rising into rarer, narrow, sharply rounded riblets, sepa- 

 rated by flat intervals of fully twice their width ; on the carina 

 they rise into sharpish little longitudinal tubercles ; below this 

 they rapidly and almost wholly disappear, showing on the base 

 only as slight undulations marking the very curved lines of 

 growth. Besides these there are minute round threads which fret 

 the whole surface. Spirals. The base of each whorl is thrown out 

 into a narrow sharp expressed carina, which is rendered more 

 prominent both by the longitudinal tubercles and by the imbri- 

 cation of the whorls, which project markedly above the suture ; 

 the whole surface of the shell is, moreover, covered with fine un- 

 equal rounded threads, which are coarser in proportion to the 

 development of the longitudinal puckerings, and which are crisply 

 crimped by the finer longitudinals. On the base a slight swelling 

 runs round near the outer edge. Colour a dead, faintly yellowish, 

 chalky white, but which is not altogether without polish. Spire 

 very high and narrow. Apex broken. Whorls. Only 4 remain, 

 of very regular increase ; flatly and very straightly sloping down 

 from the deep suture to the carina, below which they are sharply 

 constricted ; each whorl is thus imbricated over the one which 

 succeeds it. Suture squarely angulated and deeply impressed. 

 Mouth squarely rounded, rather small. Outer lip thin. Pillar-lip 

 broadly reflected over the umbilicus. Umbilicus small but deep, 

 with a narrow swollen edge. H. 0*9 (?). B. 0-65, least 0-58. 

 Penultimate whorl 0'2. Mouth, height 025, breadth 0-25. 



The only specimen of this species is badly broken, so that the 

 measurements, that of height in particular, are somewhat ima- 

 ginary. It is so remarkable a form, however, that it is well worth 

 preservation and description. In the absence of apex, operculum, 

 and animal, its generic place is somewhat doubtful. The texture 

 of the shell rather suggests a Solarium, but its extraordinarily high 

 and narrow form, its almost poriform umbilicus, and the character 

 of its sculpture point more to Echinella. In shape it resembles 

 Helix Schrarnmi, Fischer (Journ. de Conch. 1858, p. 184, pi. vii. 

 f. 8), more than any thing else I know. 



