SUB-ORDER B 



RHIPIDOQLOSS4 





Bellerophon, Montf. (IVaagenia, <!.- K-.n.), (Fig. 806). Slu-11 j:lol....-.- i,r li-.-.ilal. 

 more or less convolute, and narrowly umbilicatf on both sides. Aj..-i-tiiiv Mil.-i-iirular 



or oval, with a dri-p iii.-<liaii 

 ^inii- ; .>lit-liaii<l cith.-i <li~- 

 tinct or r.-plarnl 1,\- a k.-i-l, 

 sometimes absent. Outer 



Fio. 806. 



Bellerophon bicarenus, Leveille. Carboniferous ; Tournay, 

 Belgium. 



s07. 



Klein. Curb" 1 

 burg. 



FIG. 808. 

 Cyrtolites ornatus, Conrad. A , Speci- 



lip sharp, columellar edge often with callus. External surface marked only l>y 



growth- lines. Silurian to Permian; muximum in 

 Carboniferous. 



Sub-genera: Bucania, Hall. Silurian ami Devonian. 

 Warthia, Mogulia, Waagen. Carboniferous 



Euphemus, M'Coy (Fig. 807). Like Bellerophon, 



but the inner whorls, and a part of the last, spirally 

 striated. Carboniferous. 



Salpingostoma, Roem. Shell widely umbilicate, 

 the aperture suddenly becoming greatly dilated. 



men viewed from one side, from o'rdo- Whorls traversed along the middle by a slit closed 

 viclan of Boonville, New York (after . . , , i a-i j T 



F.Roemer). B, Anterior aspect of speci- anteriorly and posteriorly. Silurian and Devonian. 



ohio fr m Ordovician of Cincinnati ' Trematpnotus, Hall. Like the last, but tin- .-lit- 



band replaced by a row of perforations. Silurian. 



Cyrtolites, Conrad (Fig. 808). Shell widely umbilicate, keeled, with- nit >lit, and 

 with strong transverse ribs. Cambrian to Carboniferous. 



Family 4. Fissurellidae. Risso. 



Shell symmetrical, cap- or limpet-shaped, non-nacreous, without operculnm. Apex erect 

 or pointing backward, often recurved, perforated. Anterior margin often with a fissure : 

 young shell with a spiral nucleus. Marine; shore forms. Carboniferous to Re.vnt. 



Of the three sub-families into which this group is divided, the Fissun ///;/" an 

 known only in the recent fauna, Fissurellidinae occur in the Pliocene ; 

 all the earlier forms are Emarginulinae. 



Fissurella, Brug. Shell conical, oval, with an oval apical orifice 

 bounded inside by an entire callus. Recent. The numerous fossil 

 species referred to this genus belong to Fissuridea. 



Fissurellidea, d'Orb. ; Pupillaea, Gray ; Megatebennus, Lucapiv //", 

 Pilsbry ; Macroschisma, Swains. These are all recent genera, with 

 the apical orifice very large. 



Lucapina, Gray. Like Fissurella, but with large apical orifice 

 and finely crenate periphery. Pliocene and Recent. 



Fissuridea, Swains. (Glyphis, Cpr. ; Fissurella, auct), (Fig. 809). 

 Shell conical, oval, with apex in advance of the middle, giving place 

 to a perforation which is bounded inside by a posteriorly truncate callus. 

 iferous (?) to Recent ; very abundant in the Tertiary. 



Pro. BOO. 



I 



Bfr. Miucfiit-; 

 . Hungary. 



Carbon- 



