PROPILIDIUM. 443 



PROPILIDIUM, Forbes and Hanlev. 



Shell obovate, conical, with an eccentric posteal apex ; 

 surface with radiating striae ; interior with a crescentic 

 muscular impression interrupted in the region of the 

 head. 



Animal with two subulate tentacles unprovided with 

 eyes ; mantle-margin simple ; branchial plume (two 

 plumes ?) cervical ; foot large, orbicular, with plain sides ; 

 buccal mass with corneous jaws and a lingual riband, like 

 those of Pilidium. 



We have constituted this genus for a very remarkable 

 and rare mollusk, which, whilst its shell reminds us 

 strongly of an Emarginula without a slit and has a vertex 

 holding the same position with respect to the head of the 

 animal — an arrangement rarely seen among the Patellidte — 

 has its soft parts very similar in most respects with those 

 of Pilidium. It presents considerable resemblance to 

 some limpets referred to the genus JScutella, but not 

 sufficient to permit us to refer it to that group. In 

 Scutella Arabica there are two powerful muscular scars, 

 one on each side of the interior of the shell, which seem to 

 indicate differences of consequence in the animal. 



P. Ancyloide, Forbes. 



Plate LXII. figs. 3, 4, 5, and (Animal) Plate A.A, fig. 4. 



2 Patella cceca, Mui.ler, Zoolog. Danic. i. p. 45, pi. 12, f. 1, 2, 3, from which 

 (I.mel. Syst. Nat. p. 3711, and Dillw. Recent Shells, vol. ii. 

 p. 1052. 

 „ ? Ancyloides, Forbes, Ann. Nat. Hist. vol. v. (1840) p. 108, pi. 2, f. 16. 

 — Brit. Marine Conch, p. 133. 

 7 „ Candida, Couthouy, Boston Journ. Nat. Hist. vol. ii. p. 86, pi. 3, f. 17. 

 — Gould, Invert. Massach. p. 152. — Dekay, New York 

 Fauna, Moll. p. 161. 



