298 Mr. R. Etheridge, Jun., on the Gasteropoda 



Sow., 0. tubifer, Sow., G. auricularis, Martin (=G. neri- 

 toides, Phill.), &c. 



2. Oethonychia, Hall. — Shell arched or straight, forming 



an elongated cone. Type P. subrectum, Hall. 

 A single specimen occurs in the " Gilbertson collection," 

 which is probably an example of this section. 



3. Igoceeas, Hall. — Surface cancellated. Type P. plicatum, 



Hall. m . 



In all probability, Capulus striatus, Phillips, when perfect 

 will assume this condition of ornamentation, and be the British 

 representative of the section. 



4. Exogyeoceeas, Meek and Worthen. — Forms with a 



sinistral spire and an obscure columella. Type P. re- 

 version, Hall. 

 Unknown to me as British. 



Natica ampliata, Phillips (p. 224, t. 14. 

 figs. 21 & 24). 



The collection contains the originals of both the foregoing 

 figures. The expanded outer lip, flattened inner lip, de- 

 pressed and even concave spire render this a peculiar species 

 amongst the other Carboniferous Naticiform shells. The 

 ornamentation is equally characteristic, consisting of regular, 

 even, flattened, filiform lines, or, as Prof. M'Coy has well de- 

 scribed them, minute ribs, following the marginal outline of 

 the shell. The figure of the larger example is fairly good ; 

 but a concavity which exists around the suture is hardly re- 

 presented. The spiral fine striee (mentioned by M'Coy) 

 crossing the ribs I have not seen ; but I find that, under a 

 strong lens, the ribs themselves are traversed by fine parallel 

 striae. 



In N. ampliata the apex is depressed and even somewhat 

 concave, the inner lip broad, flat, sloping inwards, plain, and 

 without any tubercle or callosity. 



Under the name of Nerita spirata, Mr. J. de C. Sowerby 

 figured two species. The larger of his two figures is the 

 present species, N. ampliata, and possesses all the characters 

 of it. The second figure given in the ' Min. Conch.' is a 

 small individual of the variety of Natica elliptica, Phill., with 

 the slightly elevated spire. The description given by 

 Sowerby — viz., " Spire small, partly immersed, the upper 

 part of which is flat, when old concave ; aperture transversely 

 oval" — is almost sufficient to show the identity of the two 

 forms. Sowerby's collection contains a second specimen 

 larger than that figured by Phillips. 



Under these circumstances the name Natica ampliata, Phill., 



