CASSIS 



Species 4. (Fig. «, h, c, d, Mus. Cuming.) 

 Cassis decussata. Cass, testa ovatd, compressiuscula, 

 ■spird siibacuminatd, apice acuta ; anfractibus univari- 

 cosis, striis elevatiuscidh lorujitudinalibus, incisisque 

 Iransversis nndique dectissatis, prcecipne ad spiram; 

 varicibus stiperne pectiliarUer bi-tri-dentato-spinosis, 

 columella fortiter pUcato-ncgatd ; Uvido-ceerulescente, 

 maculis quadratis vel str'ujis fitlvis longititdinaliter 

 midatd, maculis strigisve super varices et aperlurte 

 fauce interne castaneo-nifis. 

 'I'he decussated Helmet. Shell ovate, rather com- 

 pressed, spire somewhat acuminated, sharp at the 

 apex ; whorls one-varicose, decussated throughout 

 with rather elevated longitudinal and engi-aved trans- 

 verse strife, especially ou the spii-e ; varices peculiarly 

 two-three-deutately spinous at the upper part ; colu- 

 mella strongly plicately m-inkled ; livid blue, longitu- 

 dinally waved with fulvous streaks or square spots, 

 interior of the aperture and spots or streaks upon the 

 varices deep chesnut-red. 

 Lam.vuck, Anim. sans vert. (Deshayes' edit.) vol. x. p. 29. 

 Biicciniiiii decmsatum, LinnKUs. 

 Cussidea decussata, Bruguiere, 



Hnh. ? 



Ill this species the striped and tessellated designs of 

 painting which charaterize the C. areola and vndata are 

 united, the varieties being unaccompanied by any dif- 

 ference of form or scidptuj-e. The eliief peculiarity in the 

 sculpture of C. decussata, the same in both varieties, con- 

 sists in the longitudinal stria; being raised, whilst the trans- 

 verse striiE are engraved ; in other words, the former are 

 ridges, the latter grooves. Another feature to be remarked 

 is that the varices, including that which forms the reflected 

 maririn of the aperture, are armed at the summit, next 

 the spire, with two or three dentate spines which in all 

 other species, where they occiu-, are at the base. 



i\I. Deshayes remarks in a note on C. decussata (Anim. 

 sans vert. vol. x. p. 9.) that Lamarck in rcl'erring to 



Martini's figm-es (Couch. Cab. vol. 2. f. 360-1, and 367- 

 8.) has confounded a young specimen of his C. zebra (C. 

 undata) with it. This is a mistake : Lamarck was perfectly 

 correct, and so was Martini, who, although he describes 

 each of these shells separately, refers them both to the Buc- 

 cinum decnssatuni of Liimasus. They represent truly the 

 species in different states, and perhaps the most extreme. 



Species 5. (Mus. Brit.) 



Cassis Madagascabiensis. Cass, testa sub-trigono- 

 ovatd, veidricosd, elevato-rotundatd, anfractibus longi- 

 tudinaliter subirregidariter striatis, transversim super- 

 fcialiter sulcatis, triseriatim tubermdatis, tubercidis 

 snpreniis grandibits, prominerdibus ,- columella profuse 

 plicato-rugatis, rugis hie illic bifurcatis, labro latmime 

 expanso, marginibns conjnnctis, labro extemo intus con- 

 spicue dentato ; caruleo-albicante, facie eticausticd ru- 

 fescente-iiicarnatd, dentibm rugisque albis, interstitii'i 

 intense purpureo-casta/ieis. 

 The Madagascar Helmet. Shell somewhat triangu- 

 larly ovate, veutricose, elevately rotundate, whorls 

 longitudinally somewhat irregulai-ly striated, trans- 

 versely superficially grooved, encircled with three 

 rows of tubercles, of which the uppeiinost are large 

 and prominent; columella profuselyplicately wrinkled, 

 wi-inkles here and there bifurcated, lip very widely 

 expanded, margins joined, outer lip conspicuously 

 toothed witliin ; bluish white, enamelled face reddish 

 flesh-coloured, teeth and wrmkles white, interstices 

 intense purple-chesnut. 

 Lamarck, Ajum. sans vert. vol. x. p. 20. 

 Hab. Madagascar. 



Tliis fine species may be recognised by the delicate flesh 

 tint of its enamelled face and deep purple-chesnut coloiu-ing 

 of the Up and columella ; it attains almost as large a size 

 as the C. coniutus. Li sculptm-e it diflers from that species 

 in having the surface transversely rather supei-ficially 

 sirooved, not cancellated. 



