338 MOLLUSCA. TORNATELLAD^E. Bellkrophox. 



" Shell glossy, white, veined like ivory in a longitudinal direction, and 

 furnished with eight or nine reversed volutions, slightly tapering to an ob- 

 tuse point ; the lower whorl occvipies two-thirds of the shell ; the aperture 

 is narrow, not quite half the length of the shell ; and the columella possesses 

 one plication. Length a quarter of an inch ; breadth one-third of its length." 

 Mont. — This species, in all probability, is likewise the type of a new genus. 



Gen. BELLEROPHON. — SheU spiral, involute, the last 

 whorl enclosing the others ; aperture arched, extremities 

 simple, with a sinus in the middle of the outer lip. 



* With a mesial band. 



1. B. hiulcus. — Globose, expanded ; closely striated, the striae sharp, ele- 

 vated, passing obliquely from the mesial band, which is flat, broad, with its 



sides defined by sharp depressed lines ; a central cavity on each side Conchy- 



liolithus Nautilites hiulcus. Mart. Pet. Derb. t. xl. f. 2 — Bel. hiulcus, Sower. 

 Min. Conch, t. cccclxx. f. 1 — Carboniferous limestone, Derbysliire. 



2. B. temnfascia — Spherical, with a well defined central cavity, finely stria- 

 ted; mesial band linear, elevated. — Conch. Naut. hiulcus, var. c. Mart. Pet. 

 Derb. p. 15.— B. ten. Sower. INIin. Conch, t. cccclxx. f. 2, 3, — Carboniferous 

 limestone, Derbyshire and Yorkshire- 



3. B. costatus. — Globose, expanded, subcarinated, with slender sharp ribs 



diverging from the undefined broad convex band ; with a central cavity 



Conch. N. hiulcus, Mart. p. 15, t. xl. f. 1. Park. Or. Hem. iii. 141. t. x. £ C, 

 7. — B. cost. Sower. Min. Conch, t. cccclxx. f. 4 — Carboniferous limestone, Der- 

 byshire. 



4. B. deciissatus Shell somewhat ovate longitudmally, with numerous 



spiral I'idges, crossed by finer ones, giving the points of union a subtubeixu- 

 lar aspect ; mesial band rounded, longitudinally striated, decussated by the 

 transverse fine ridges, which in crossing have a concave bend — In my cabi- 

 net from slate-clay of flie coal formation, Linlithgowshire. 



5. B. striatiis — Longitudinally ovate ; with numerous, fine, sfightly rough, 

 spiral ridges: mesial band slightly fliittened, and longitudinally striated. 

 This species diifers from the last in the mesial band being more elevated, 

 and in the nearly total absence of the transverse ridges. In one specimen 

 there is a thick inner lip spreading on the surface of the last whorl. — From 

 the same place as the last. 



** Destitute of a mesial band. 

 C. B. apertus — Nearly spherical ; sides of th.e aperture expanded ; shell 

 smooth, thick ; with a well defined central cavity — Sou-er. Min. Conch. 



t. cccclxix. f. 1 In Carboniferous Limestone, Lowth. I have a specimen fi-om 



carboniferous limestone in Linlithgowshire, agreeing in form with one pre- 

 sented to me by Mr Wright from Lowth. 



7. B. cornu-arictis. — Elongated ; sides of the aperture expanded ; shell very 

 thick, smooth, faintly marked by the lines of growth. The shell, when a little 

 corroded, becomes coarse and laminated — NautUus, Ure, Hist. Ruth. 308. 



t. xiv. f 8 B. corn. Sower. Min. Conch, t. cccclxix. f. 2 — INIr Sowerby's 



specimens are from Limestone, Kendal ; mine are from Carboniferous Limestone, 

 Linlithgowshire. 



8. B. Urii Globular ; sides of the aperture expanded ; shell smooth, re- 

 gularly sulcated spirally ; the furrows shallow, the ridges rounded.— Nauti- 



