Vol.51'] MR. R. B. NEWTON ON FOSSILS FROM MADAGASCAR. 79 



the whorl. This fragment most probably belongs to one of the 

 Indian forms described by Waagen. 



Horizon. — Jurassic (probably Kimeridgian). 



Log. — North of Andranosamonta. 



Gasteropoda. 



[Internal cast of a Patelloid shell.] 



Horizon. — Lower Oolite. Log. — 3 miles north of Iraony. 

 [A Naticoid shell] 



Horizon. — Lower Oolite. Log. — About 3 miles north of Iraony. 



jNatica, sp. [Casts.] 



Horizon. — Lower Oolite. Log. — About 10 miles S.E. of Andranosa- 

 monta village. 



Etjlima ? sp. 



This is a sandstone-impression of a small specimen, probably 

 referable to this genus ; it was found associated with Astarte 

 dejpressa, Pteroperna costatula, and Trigonia pullus. 



Horizon. — Oolite (Lower?). Log. — Antankarana province, north- 

 western boundary of the central hill-range. 



According to Mr. Baron, the sandstones containing this shell are 

 largely developed in this region, but fossils are rare. 



Trochactceonina Eichardsoni, sp. nov. (PI. II. figs. 1-3.) 



Shell subcylindrical, ventricose, sides compressed ; vertex wide, 

 depressed, containing about five whorls definitely canaliculated at 

 their sutures ; the three earliest volutions form a mammillation 

 which stands just above the level of the vertex, apex absent ; whorls 

 with rounded margins ; columella-border oblique, excavated at the 

 base, without plications, but covered with a thick spreading 

 callosity ; mouth elongate and narrow, outer lip thin ; surface orna- 

 mented with longitudinally curved lines of growth. 



Dimensions. — Length = 50 mm. ; maximum breadth = 35 mm. • 

 diameter of vertex = 33 x 30 mm. 



This specimen is referred to Meek's genus Trochactceonina 1 

 [type Actceonina ventricosa, d'Orbigny 2 ], which differs from the true 

 Actceonina on account of its large ventricose body-whorl and de- 

 pressed spire. 



The other closely allied genera are Cylinclrites, with a twisted 

 columella, and Actceonella, distinguished by its prominent columellar 

 plications. The present shell is recognized as a new species because 

 of its largo size, depressed spiral area, and compressed sides. The 

 name of Trochactceonina Richardsoni is proposed for it, in honour 

 of the Eev. J. Eichardson, of the London Missionary Society, to 



1 Am. Journ. Sci. ser. 2, vol. xxxv. (1863) p. 91. 



2 ' Pal. Fran9aise : Terr, jurassiques — Gasteropodes,' 1850, p.178, pi. cclxxxviii 

 figs. 7, 8. 



