TERTIARY MOLLUSCA. 131 



to the beak, are higher, narrower, and more rugose than in P. medius; 

 the number of ribs is within the range of variation of P. medius, but is 

 less by one or two than the average for specimens of the same size. 

 On the left valve the ribs are a little closer together and the lateral 

 margins are less flaring than in P. medius. The right ears are about as 

 in P. medius, but the left ears lack the two strong ribs which are nearly 

 always present near the hinge line on each left ear of the living species. 



Localities. — One-half mile inland from the pier of the Juragud Rail- 

 road, Santiago Bay, Willcox; Juragua Railroad, La Cruz, first cutting 

 on road, Vaughan; Vento, province of Havana, Wren; stations 3192, 

 3439, 4290, 5255. 



Geologic horizon. — Oligocene. 



Type.—U. S. Nat. Mus. No. 167102. 



Pecten perlatus, new species. 

 (Plate 13, Figure 3.) 

 The following is a description of this species : 



Shell small, suborbicular, tumid; ribs 16, simple except near the margin, 

 where each contains 3 riblets; interspaces as wide as the ribs; concentric sculp- 

 ture of raised, widely spaced growth lines, apparently confined to the inter- 

 spaces; submargins with close radial riblets which form an uninterrupted 

 series with those on the ears; ears large, equal, finely radially ribbed, scarcely 

 differentiated from the submargins. 



Alt., 11 mm.; lat., 12 mm. 



Locality. — Crocus Bay, Anguilla, station 6966, Vaughan. 

 Geologic horizon. — Oligocene. 

 Type.—U. S. Nat. Mus. No. 167068. 



Pecten (Chlamys) waylandi, new species. 



(Plate 7, Figures 4 a, &.) 



The following is a description of this species : 



Shell medium-sized, nearly equilateral, equivalve, with about 30 low ribs 

 with equal interspaces becoming obsolete towards the depressed submargins; 

 posterior ears small, oblique, with 4 or 5 faint radial riblets; anterior ears 

 much larger, with about 12 faint riblets on left ear and 5 or 6 somewhat 

 coarser riblets on right ear; byssal notch about one-half the length of the ear; 

 inner margin fluted in accordance with the external ribbing in channels which 

 probably extend well towards the center of the disk. 



Alt., 32.3 mm.; lat., 29 mm.; diam., 12.5 mm. 



Although the single specimen upon which this species is founded has 

 lost so much of the external part of the shell that it is impossible to 

 make out the details of sculpture, the ears, as well as the outline and 

 major sculpture of the shell, are so well preserved that it seems worth 

 while to describe it. The species is not apt to be confused with any 

 other of this region. It is named in honor of Dr. T. Wayland Vaughan. 



Locality.— Santiago, Cuba, station 3440, Vaughan. 



Geologic horizon. — Oligocene. 



Type.—U. S. Nat. Mus. No. 167121. 



