MELAMPUS. 561 
The single parietal fold is somewhat within the aperture and does not reach the 
level of the latter, and therefore may be easily overlooked; it is wanting in young 
specimens. The ridges (lire) inside the outer margin are clearly visible in nearly full- 
grown examples, but almost disappear in the largest full-grown one; in some young 
specimens these are not to be seen, in others they are also visible outside in the form 
of narrow white bandlets. The columellar fold is well developed in all stages of 
growth. 
B. Trauia, Gray. 
7. Melampus panamensis, (Tab. XLIII. figg. 10, 10a.) 
Auricula panamensis, C. B. Adams, Ann. Lyc. Nat. Hist. N. York, v. p. 483 (1852) *. 
Tralia panamensis, H. & A. Adams, Gen. Recent Moll. p. 244’. 
Melampus panamensis, Pfeiffer, Monogr. Auric. p. 48°; Catal. Auric. Brit. Mus. p. 35+; Dall, 
Proc. Acad. Phil. 1900, p. 97°. 
Hab. W. Costa Rica: Punta Arenas (Biolley). 
S. Panama: Panama and Taboga I., under stones at high-water mark, or crawling 
over. wet stones (C. B. Adams’). 
Cocos I. (Snodgrass & Heller®). 
This is the Pacific representative of the West-Indian JZ. pusillus, Gmel. (Auricula 
nitens, Lam., Martini, Syst. Conch.-Cab. 11. t. 43. fig. 446; ibid. new edition by 
Kiister, Auriculaceen, t. 2. figg. 11-13; Pfeiffer, Monogr. Auric. p. 47; Catal. Auric. 
Brit. Mus. p. 34; Tryon, Am. Journ. Conch. iv. t. 18. fig. 9), which may yet be found 
on the Caribbean coast of Central America. It differs from M. pusillus in its smaller 
size and more slender shape, and in the more oblique position of the lower parietal 
fold. We give figures of 1. panamensis from specimens in Petel’s collection, now in 
the Berlin Museum, these varying in the comparative breadth. Amongst more than 
twelve examples obtained at Punta Arenas by Mr. Biolley, none measure more than 
8 millim. in length, 4 in breadth, and 53 in the aperture. 
Doubtful species, without ridges inside the outer margin, none of them figured. 
8. Melampus(?) concinnus. 
 Auricula concinna, C. B. Adams, Ann. Lyc. Nat. Hist. N. York, v. p. 432 (1852) *. 
Ophicardelus concinnus, H. & A. Adams, P. Z. S. 1854, p. 84°. 
Melampus concinnus, Pfeiffer, Monogr. Auric. p. 57°; Catal. Auric. Brit. Mus, p. 43°. 
Hab. S. Panama: Panama, on the short suckers which were growing up thickly beneath 
; 1 
the mangroves near high-water mark. 
9. Melampus (?) infrequens. 
Auricula infrequens, C. B. Adams, Ann. Lyc. Nat. Hist. N. York, v. p. 433 (1852) '. 
BIOL. CENTR.-AMER., Terr. and Fluviat. Mollusca, October 1900. 71 
