TURRITELLA. 227 
Family—TURRITELLIDA. 
** Shell imperforate, turrited, many-whorled, conical, elongate; apertwre small, 
rounded, oval, or sub-quadrangular, entire or slightly notched at the base; lip 
simple, arched, or sinuous ; operculum corneous . . . .’—FiscHEr. 
It is quite possible that Cerithinella and even Pseudalaria, which I have placed 
provisionally under the Crriruipm, should be regarded as belonging to this 
family. 
Genus—TurriteLLA, Lamarck, 1801. 
** Shell elongated, many-whorled, spirally striated; aperture rounded, margin 
thin, operculum horny . . . .?—S. P. Woopwarp. 
As restricted by Fischer the family of the Turritellide is mainly composed of 
this one genus, which, he says, commences in the Lias, and embraces more than 
400 species of fossils. §. P. Woodward, on the other hand, traced the genus no 
further back than the Neocomian. There can be little doubt, however, that 
fossils with a very strong resemblance to existing Twrritelle are far from uncom- 
mon in the Lias, and several species, yielding remarkably handsome shells, occur 
in the Inferior Oolite of this country. 
It is just possible that some of these species might be referred to Semper’s 
genus, Mathilda, but only, perhaps, in a subgeneric sense. Laube described and 
figured a small shell, 9 mm. in length, from the Brown Jura of Balin, under the 
name of Mathilda euglypha (vide postea, p. 235). He also refers to Turritella 
eucycla, Héb. and Desl. (‘ Foss. Mont.-Bellay,’ p. 47, pl. ii, fig. 11) as belonging 
to the genus Mathilda. The authors of this last-quoted work observe that their 
Lurritella eucycla greatly resembles “ Cerithiwm” zic-zac, Desl., from the Lias, 
and “ Cerithium” amenum, Desl., from the “‘ Odlite ferrugineuse,” although 
specifically distinct. All these fossils are Turritellids, and they appear to be 
related to each other so as to constitute a group. 
Attention has been drawn lately by Mons. Cossmann (Kt. Bath., p. 221) to 
the probability of many of these Jurassic Turritellas belonging to the genus 
Mathilda, as suggested by Laube. He has, in fact, discovered the peculiar sinistral 
apex and “embryonic button,” held to be one of the characteristics of Semper’s 
genus, in the species named by him Mathilda Janeti. He describes eight species 
in all from the Bathonian of France under the genus Mathilda. 
