154 MOLLUSCA FROM THE CRAG. 



prominent, with the upper part of the volution somewhat projecting, giving the outer 

 Hp a straighter form than in the other species ; the inner Up or columella is somewhat 

 oblique, flattened, and narrower than in the preceding species, with a less regularly- 

 ovate aperture ; the outer lip is less curved, giving a slightly angular form to the 

 opening. 



Some of my specimens are very imperfect ; more and better materials are required 

 to determine the species. From its difference of form I have presumed it to be new, 

 though its present name may be considered only as a provisional one. 



Capulus,* De Monffort, 1810. 

 Patella (spec.) Linn. 

 Peleopsis. Lam. 1815. 

 Amalthea. Schum. 1817. 

 AcTiTA. Fisch. (Hermansen.) 

 Pilopsis. Koniff. 

 Brocchia. Bronn. 

 ACROCULIA. Philhps. 

 Cyrtholithes. Vanuxem. 



Gen. Char. Shell obliquely conical, with a broad expanded base, and a slightly 

 recurved apex; aperture large, generally elliptical, sometimes circular; muscular 

 impressions united posteriorly ; rounded and enlarged in front, with an opening 

 between them for the head of the animal ; in a recent state, covered with a thick 

 epidermis. 



This genus is well distinguished from Patella by the position of the apex, which is 

 situated on the posterior part of the shell, and is generally a little recurved, whereas, in 

 Patella, it is on the anterior, and is simply conical; the muscular impressions, or rather 

 impression (for the two are united into one ligulate band), is therefore on the posterior 

 part, with an opening between the obtuse terminations, for the egress of the animal's 

 head, and is joined behind under the apex. Species from the Palaeozoic Rocks 

 have been formed into a genus by Philhps, under the name Acrocuha, in consequence 

 of an obhquity in its recurved apex, which character alone is insufficient for generic 

 distinction, and from the excessive variableness of some of my Crag fossils, such 

 character may be almost doubted as sufficient for even specific determination. 



* Etym. (?) Capulus, a haiulle. 



