DALL: MOLLUSCA AND BRACHIOPODA. 357 
Mopaludae. 
PLACIPHORELLA CarPENTER. 
Placiphorella blainvillei Bropertr. 
Chiton blainvillet Broderip, P. Z. S. Lond., 1832, p. 27; Reeve, Conch. Icon., Mon. 
Chiton, pl. 8, fig. 13. 
Mopalia blainvillei Gray, P. Z. S. Lond., 1847, p. 69. 
FPlaciphorella blainvillei Dall, Proc. U. S. Nat. Mus., 1886, 9, pp. 210, 211; Pilsbry, 
in Tryon, Man., 1892, 14, p. 310, pl. 66, figs. 26-32. 
U.S. 5S. “ Albatross,” station 3368, near Cocos Island, Gulf of Panama, in 66 
fathoms, rocky bottom; U.S. N. Mus. 122,968. Original locality of the species 
Lobos de Tierra Island, Peru, on a stone from seventeen fathoms (Cuming). 
SCAPHOPODA. 
SOLENOCONCHIA. 
Dentaludae. 
Dentalium megathyris Datt. 
Plate 19, figure 1. 
Dentalium megathyris Dall, Proc. U. S. Nat. Mus., 1889, 12, p. 293, pl. 9, fig. 1; 
Stearns, op. cit., 1893, 16, p. 424; Pilsbry, Mon. Scaphopoda, Man. Conch., 
1897, 17, p. 67, pl. 15, figs. 29, 30, 31. 
The following table shows the distribution of this species as far as.known : 
Station. Locality. Depth. Bottom. Bottom temp. F. Mus. Reg. 
*3360 Gulf of Panama 1672 sand 86°.4 122,982 
*3361 oo 1471 ooze 36°.6 122,977 
*3381 sf e 1772 mud 35°.8 122,975 
3399 Gi of 1740 ooze 36°.0 122,980 
3407 off Galapagos Ids. 885 se 87°.2 122,978 
8413 “ a: 1360 sg 386°.0 122,979 
3431 Gulf of California 995 mud 37°.0 122,976 
3432 a Sy 1421 wy 37°.8 122,981 
3414 off Tehuantepec 2232 @ 388°.5 122,974 
2788 off Chiloe Id. 1050 36°.9 110,665 
2789 off S. W. Chile 1342 : 85°.9 87,558 
2807 off Galapagos Ids. 812 ooze 38°.4 117,880 
As in previous instances the specimens in nearly all cases were badly eroded. 
A considerable range of variation was observed in the matter of curvature, some 
being straighter than others taken in the same haul of the dredge, some thinner- 
shelled, in many individuals the aperture being almost absolutely circular. 
