Cassis. 



MOLLUSCA. 



53 



Genus XV. — CASSIS. — Bruguiere. 



Shell ventricose, gibbous, mostly subtrigonal ; spire 

 generally very short ; aperture longitudinal, narrow, in 

 some species nearly equal to the whole length of the 

 shell, in others proportionably wider (in which case the 

 aperture can hardly be considered as elongated) with a 

 more produced spire ; base of the aperture terminating 

 in a short canal, abruptly reflected on its inner margin, 

 i which is acute; columella twisted or rugose, and pro- 

 vided with transverse plaits ; outer lip usually thickened, 

 inflected, and spread over the lower part of the body, 

 producing a flattened disk reaching beyond the edge of 

 the lower varix, internally dentated, and in various 

 species forming a varix at the completion of each volu- 

 tion. 



1. C. BiCATiNATUS The Double-Chained Cassis, pi. 



XXXIII. fig. 7, 8. 



Cassis bicatinatus. Sowerby, Min. Conch. II. p. 117, pi. 

 151, fig. 1, 2. 



Shell ovate, ventricose ; spire of medium length, consisting 

 of five well defined volutions, and terminating in an obtuse 

 apex ; whole surface traversed by numerous, transverse, promi- 

 nent, narrow ribs, with broad intermediate furrows, decussated 

 by small, slightly oblique longitudinal costEe upon the superior 

 portions of the volutions, most distinct upon the central volu- 

 tions, giving a chain-like appearance to two or three pairs of 

 the furrows, but becoming obsolete below ; aperture ovate, 

 somewhat straitened towards both extremities, and ending in a 

 short canal ; pillar lip spreading broadly over the columella, 

 which is slightly plaited and extending over an open umbilicus; 

 outer lip thickened, rounded, reflected, and obscurely tubercu- 

 latod within. 



Discovered in the Crag at Bawdsey, Suffolk, by the Rev. J. 

 Lambert, of Trinity College, Cambridge. 



Genus XVI.—CASSIDARIA Lamarck. 



Shell obovate, ovate or oblong ; ventricose ; body very 

 large ; spire short ; aperture longitudinal, narrow, ter- 

 minating at the base in a recurved canal, which points 

 upwards when the shell is placed with the aperture 

 downwards ; outer lip marginate, thickened, reflected, 

 and frequently dentated within ; inner lip expanded, 

 covering the lower part of the body and columella, but 

 detached from it at the base, immediately above the 

 canal, which in some species is rough, granular, tuber- 

 culate or rugose; outer surface generally grooved, tuber- 

 culated, and covered with a thin, horny epidermis. 



1. C. CARINATA. — The Keeled Cassidaria, pi. XXXIII. 

 fig. 1, 2. 



Cassis carinata. Sowerby, Min. Conch. I. p. 23, pi. 6, three 

 upper figures. Morio carinata, Fleming, Brit. An. p. 340. 



Shell pyriform ; body very large, obliquely flattened above ; 

 spire very short, consisting of five or six abruptly tapering, de- 

 pressed angular volutions, terminating in an acute apex ; body 



with three remote, nodulous transverse ribs, and numerous, 

 close, undulous, transverse, alternately large and small stria?, 

 which are decussated by many lines of growth ; aperture 

 oblong, straitened both above and below, and ending in a nar- 

 row recurved beak ; pillar lip concave, very broadly reflected 

 on the columella, with numerous tooth-like processes on its 

 inner margin, and two or three on the inner margin of the 

 outer lip ; outer lip broad, continuous above, smooth on the 

 margin, and extending over the umbilicus. 



Found in the London Clay at Highgate Hill. 



2. C. STRIATA The Striated Cassidaria, pi. XXXIII. 



fig. 3, 4. 



Cassis striata. Sowerby, Min. Conch. I. p. 24, pi. 6, four 

 lower figures. Fleming, Brit. An. p. 339. 



Shell ovate; body large; spire small, consisting of five or six 

 rounded, abruptly tapering, volutions, terminating in a sharp 

 apex ; whole shell covered with transverse wide-set striae ; a 

 spiral ridge of transversely oblong nodules invest the superior 

 portion of the body, which is also crossed by indistinct lines of 

 growth ; aperture greatly elongated, narrow, and contracted at 

 both extremities ; pillar lip much reflected on the columella, 

 broad above and narrowing towards the base, which is provided 

 with a narrow, slightly bent canal, and toothed within ; outer 

 lip broad, plicated internally, and reflected over the umbilicus 

 behind. 



Found in the London Clay at Highgate Hill. 



FAMILY IV.— ALATA. 



Shell provided with a canal of greater or less extent, 

 situate at the base of the aperture; the right lip changes 

 its form as the aniinal advances in age, and is jnovided 

 with a sinus at the lower part. 



Genus XVII ROSTELLARIA.— /.o««/t/(. 



Shell turreted or fusiform; spire uniformly longer than 

 the aperture ; the superior volutions generally longitudi- 

 nally grooved; aperture oblong, its upper part prolonged 

 into an elongated narrow canal, which in some instances 

 extends to the apex of the spire, and not unfrequently 

 turns down on the opposite side ; base with a more or 

 less lengthened canal, pointed beneath ; outer lip in the 

 infant state, thin, but becomes greatly dilated with age, 

 entire, or dentated at its lower margin, or digitated; 

 outside covered with a thin horny epidermis ; aperture 

 provided with a thick corneous operculum of an oblong 

 form, rounded at one end and pointed at the other. 



SECTION I. OUTER LIP EXPANDED. 



1. R. MACROPTERA The Loug-Winged Rostellaria, pi. 



XXXin. fig. 17, 18, 19. 



Rostellaria macroptera. Lamarck, Env. de Paris, p. 48. 

 Lyell's Bits, of Geology, p. 310, fig. 138. Fleming, Brit. An. 

 p. 360. Sowerby, Min. Concb. IIL p, 177, plates 298, 299, 



o 



