202 fissurellim;. 



paululum elevato ; foramine maximo, ovali, albo marginato. Obs. 

 A large shield-like species. 



124. Hanleyana (f. 174), Sowb. G. B. 2.— Parva, alba, sub- 

 depressa, antice angustata, minute eancellata, intiis alba, mar- 

 gine leviter crenulata; foramine subtrigono, lateribus aculeatis, 

 prope medium posito. Obs. The triangular fissure in this species 

 has a little elevated point at each side. 



Gends FISSURELLLDEA. 



Char. Gen. Molluscum gasteropodum, testa patellarformi, dorsali 

 pallio tecta ad apicem, fissura magna perforata, margine aperturse 

 ad extremitates elevato. 



The characters of the shells alone are not sufficient to distin- 

 guish this genus from the preceding, although the fissure is larger 

 than in Fissurella, and the basal margin is elevated at both ends ; 

 but in F. hiantula the shell is covered almost entirely by a lobe 

 of the mantle, and although the animals of the other species are 

 not all known, I have placed together those whose shell would ap- 

 pear probably to belong to the same type. 



Species of Fissurellidea. 



1. hiantula (f. 193, 194, 1 95), Lamk. — Testa oblonga, antice 

 subangustata ; lateribus compressis, terminis elevatis ; impresso- 

 striata griseo, olivaceo vel rubro varie radiata et picta, intiis alba ; 

 callo valido, margine leviter crenulato ; foramine magno, ovali, 

 paululum infr<a medium posito. Obs. Rather narrower anteriorly, 

 and, by being as it were pinched in at the sides, the basal margin 

 is open at both ends. 



2. Chemnitzii (f. 29, 192), Sowb. — Ovali, crassa, antice an- 

 gustata, lateribus compressis, roseo radiata, concentrice undulatim 

 striata, costis complanatis et interstitiis minoribus radiata, intiis 

 alba; callo valido ; foramine magno, ovali, subcentrali. Obs. A 

 large, thick flat-ribbed, rose-rayed shell. 



3. flouesceks (f. 202, 203), Soiob. G. B. 2.— Oblonga, tenui, 

 antice angustata, subdepressa,, terminis paululum elevatis, con- 

 centrice undulatim striata, costis depressis insequalibus radiata, 

 fulva, rufo variegata, intiis alba ; margine crenulato, roseo, callo 

 apicale roseo marginato; foramine magno, paululum infra medium 



