MAZATLAN UNIVALVES 297 



Tablet 1462 contains an extremely young sp. with the helicoid 

 apex. 1463, 2 young sp., one on Byssoarca solida. 1464, 1 sp. 

 with exterior beautifully perfect. 1465, 2 sp. one very flat, 

 the other very conical. 1466, 2 distorted sp. of which one is 

 shaped like Amathina, Grray 1467, 1 sp. probably old, with 

 the margin narrowed inside by non-serrated laminae. 1468, 

 3 sp. shewing basal supports on the outside. 



347. HIPPONYX ANTIQUATUS, Linn. 



Patella antiquata, Linn. Syst. Nat. p. 1259. Gmel. p. 3709. 



Mont. Test. Brit. p. 485, pi. 13, f.$.Dillw. Descr. Cat. 



p. 1035, no. 44. 



=Lepas alba, Mart. Conch, pi. 12, f. 111-2. 

 + Patella Mitrula, Gmel. p. 3708. 

 + Patella nivea, Gmel. p. 3727. 

 Le Soron, Adams. Sen. p. 32, pi. 2, f. 3. 



Pileopsis antiquata, Forbes fy Hani. Br. Moll. vol. ii. p. 462. 

 Hipponyx antiquatus, Mke. in Zeit.f. Mai. 1853, p. 79. Proc. 



Zool. Soc. Jan, 1856, p. 3. 



Cochlolepas antiquatus, H. fy A. Ad. Gen. i. 373. 

 = Pileopsis mitrula, Lam. An. s. Vert. vol. vii. p. 610, no. 2. 

 Capulus mitrula, DwnJc. Ic. Moll. Guin. p. 36, no. 99. J?. M. 



Cat. Cuba Moll. p. 32, no. 390. 

 Hipponice mitral e, Defr. Journ. Phys. 1819, f. 4. Blainv. 



Malac. pi. 50, f. 4. 

 Hipponyx mitrula, Sow. Proc. Zool. Soc. 1835, p. 5 : do. Thes. 



Conch, (inter Brachiopoda, 'Nov. 1846) p. 369. no. 2, pi. 73, 



f. 1820. 



Hipponyx Panamensis, C. B. Ad. Pan. Shells, p. 218, no. 328- 

 Amalthea Panamensis, H. fy 'A. Ad. Gen. i. 374. 



Known from H. serratus by the rounded base. Sowerby's 

 species was described, as of Lam. from Peruvian shells brought 

 by Mr. Cuming. Prof. Adams, finding certain differences of 

 form and markings between his Panama and Caribbean speci- 

 mens, gave the Pacific shells a fresh name. Both these and 

 the Atlantic forms are however extremely variable in shape 

 and details of sculpture. Only three Mazatlan shells are 

 referable to this species ; one, although only 'D62 long, has its 

 apex decollated, is compressed and conical, with the beak 

 much recurved, and has very fine, close, radiating striae, inter- 

 rupted by lines of growth ; the second, flattened and extremely 

 worn, is curiously indented in the region of the head ; the 



