146 AMERICAN JOURNAL 



Genus DICROLOMA, Gabb, n. gen. Plate 14, fig. 16, 17. 



Elongate, fusiform, anterior canal long and straight, or curved ; 

 no posterior canal ; outer lip with two (or more ?) long, slender, 

 digitate processes. 



D. Lorieri, D. Eudesii (both Pterocera, d'Orb. sp.). D. gracilis 

 = Rostellaria id., Miinst., D. bioarinata =Rostellaria id.., Munst., 

 D. trifida = Pterocera id. 



From the Lias and Oolite. 



Genus ALARIA, Morris and Lycett. 



Shell fusiform, spire elevated ; anterior canal more or less 

 produced, straight or curved ; no posterior canal ; outer lip digi- 

 tate, formed at one or more stages previous to the adult age, and 

 left behind by the growth of the shell, producing varices or tubu- 

 lar spines ; inner lip thin. 



A. armata, M. and L. Peculiar to the Jurassic. The original 

 description is so framed as to cover all the shells of this family, 

 as well as of the Strombidce, which are not provided with a pos- 

 terior canal, — a definition obviously too comprehensive. The 

 first species, A. armata, having a well-marked varix, must re- 

 main the type of the genus as restricted. 



Genus TESSAROLAX, Gabb. Plate 14, fig. 18, 19. 



Shell subfusiform, spire elevated ; the greater part, or the 

 whole of the spire and body whorl covered by an extension of the 

 inner lip in the adult ; anterior canal long, curved or straight ; 

 posterior canal long, running up the spire and extending beyond 

 it ; outer lip carrying two long, slender digitate processes ; the 

 incrustation of the adult shells carries one or two prominent 

 bosses or tubercles on the body whorl. 



T. distorta, Gabb ; T. bicarinata = Pterocera bicarinata, d'Orb. 

 Cretaceous. 



This genus, of which I know but two species, seems to combine 

 nearly all of the characters, except the varices, known in the 

 subfamily, and, in addition, has the encrusted surface of two of 

 the genera of Strornbidas. The tubercular excrescences, found 

 on both species, are not its least peculiar feature. 



Genus PTEROCERELLA, Meek. Plate 14, fig. 20. 



" Shell small, thin ; whorls few, rounded, smooth or subangu- 

 ated ; last one not much enlarged ; lip greatly extended and 



