FISSURELLA.— Plate XII. 



'I'm: ALTERNATE FissuRELLA. Shell oblong-ovate, sub- 

 ([uadrate, raised, a little compressed at the sides, 

 radiately ribbed, ribs narrow, with three rather small 

 ridges in the interstices, squamately decussated 

 throughout with numerous concentric furbelowed 

 lamina;, orifice subquadratcly oblong, inclined ante- 

 riorly, sides excavated in the middle ; whitish, faintly 

 spotted and raved with ash-olive, bluish in front of 

 the orifice. 



Say, (jould, MS. 



Hnh. ? 



The ribs of this species are rendered prickly by the 



delicate sqiiamate growth of the concentric furbelowed 



lamina?. 



Species 85. (Mus. Cuming.) 



Fis.surella Hdmphreyi. Fiss. kstd ovaid, crassius- 

 culd, valdi conicd, Balaniformi, radiatim fortiter cos- 

 fatd, costis nodosis ei corrurjatis, circa orificiiim alter- 

 ■natim evanidis, or/Jicio ohlongo-ooalo, subamplo, medio 

 contracto ; albd. 



Humphrey's Fissurella. Shell ovate, rather thicii, 

 very conical, Balanus-shaped, radiately strongly 

 ribbed, ribs nodose and corrugate, fading alternately 

 around the orifice, which is oblong-ovate, rather large, 

 and contracted in the middle ; white. 



Hah. Cape de Verd Islands. 



Belonging to the same type as F. glaucopis and alabas- 

 triles from the same locality, but remarkably distinguished 

 specifically by its elevated conical form. I dedicate this 

 species to the memory of the late Mr. Humphrey, in re- 

 membrance of an admirable figure of it drawn and pub- 

 lished by him in his ' Concliology, or Natural History of 

 Shells,' pi. 7. f 7. 



Species 86. (Mus. Cuming.) 



Fissurella Dysoni. Fiss. testa ovatd, acuminato-conicd, 

 lateribus compressd, radiatim squamato-costaid, costis 

 e/evatis, interstitiis nitide caucellatis, orifieio siibqua- 

 drato-oblongo , lateribus medio subexcava/is ; cariths- 

 cente-albd, intense uigro radiatd. 



Dyson's Fissurella. Shell ovate, acurainately conical, 

 compressed at the sides, radiately squamately ribbed, 

 ribs elevated, interstices neatly cancellated, orifice 



somewhat squarely oblong, slightly excavated at the 

 sides ; bluish-white, rayed with deep black. 



Hab. Honduras ; Dyson. 



A beautifully sculptured species, allii 



F. Ruppellii. 



form to 



Species 87. (Mus. Cuming.) 



Fissurella Panamensis. Fiss. testa rotundato-ovali, 

 lateribus subcompressd, radiatim teimicostatd, inter- 

 stitiis sublilissime caucellatis, orificio parvo, rotmidalo ; 

 albd, fiisco maculatd et fulguratd. 



The Panama Fissurella. Shell rotundately oval, a 

 little compressed at the sides, radiately thinly ribljed, 

 the interstices being very finely cancellated, orifice 

 small, rounded ; white, blotched and lightning- 

 marked with brown. 



Sowerby, Pro. Zool. Soc. 1831, p. 127. 



Hub. Panama (on dead shells at a depth of from six to ten 

 fothoms) ; Cuming. 

 Of a more rounded form than the preceding species, 



with a smaller and rounder orifice. 



Species 88. (Mus. Cuming.) 



Fissurella calyculata. Fiss. testa ovatd, antice sub- 

 aitenuatd, medio acuminato-conicd, tenuissimd, pellu- 

 cidd, lateribus compressd, radiatim costatd, costis jim- 

 brialo-squamatis, tribus posiicis multo majoribus, cos- 

 tarum interstitiis pulcJterrime fimbriato-clathratis, ori- 

 ficio parvo, rotundato-ovato, intus postice calycidato ; 

 pellucido-albd, roseo tinctd. 



The chambered Fissurella. Shell ovate, slightly 

 attenuated anteriorly, acuminately conical in the 

 middle, very thin, pellucid, compressed at the sides, 

 radiately ribbed, ribs fimbriately squamate, the three 

 posterior ribs much the larger, interstices between 

 the ribs very beautifully fimbriately latticed, orifice 

 small, rotundately ovate, posteriorly chambered 

 within ; transparent white, tinged with rose. 



Sowerby, Genera of Shells, No. 31. f. 4. 



Hab. ? 



It may be doubted whetlicr the inner ciiamber posterior 



to the orifice is a character of the species. The larger 



size and squamate growth of the three posterior ribs may 



be regarded of more importance. 



