MUSEUM OF COMPARATIVE ZOOLOGY. 217 
Pecten dislocatus Sar. 
Pecten dislocatus Say, Journ. Acad. Nat. Sci. Phil., ii. p. 260, 1824. 
Collected eight miles S.S. W. of Sand Key light, in 125 fms., by the steamer 
‘“‘ Bache,” in 1872, at Station 36, in 84 fms., and by Sigsbee, off Havana, in 
182 fms. The specimens obtained were dead, and perhaps disgorged by some 
fish, as this species is known to prefer water of moderate depth. No living 
specimens were obtained. The relations of this species to P. nucleus Born are 
rather close, and it is a question I have not time at present to investigate 
whether Say’s name is the first which has been given to this shell. Though 
allied to P. purpuratus Lam., it seems distinct from it. 
Pecten phrygium, n. s. 
Shell of the general form of P. asper Sby., flattish, oblique, both valves 
similarly sculptured ; left valve with about eighteen ribs with nearly equally 
wide interspaces ; these ribs have three sharp thin keels upon them, a median 
and two lateral ones, which project on the distal margin of the valve, and, with 
the similarly projecting points of four intercalary smaller keels, fimbriate the 
margin in a remarkable manner; when perfect there are rounded scallops 
thrown from keel to keel close together, like the edges of a roll of coins, which 
hide all the keels except the extreme edge of the median keel of the ribs, 
which, without projecting much, forms a raphe, connecting the scalloped sur- 
face ; the material of the scallops is very fragile, and when worn away leaves 
a totally different surface, which in this case shows a multitude of sharp thin 
scales (the bases of the scallops) zigzagging from keel to keel and imbricating 
the keels ; the ears are moderate and subequal, there are about five distant 
narrow ridges on the anterior and two or three on the posterior ear of the left 
valve, with finer intercalary threads ; the right valve has the ridges on the 
posterior ear scaly, and the byssal fasciole transversely concavely ridged; there 
are four or five free spines to the pectinium ; the cardinal margin is straight 
and internally strongly vertically striate, as in very young specimens of 
Janira or Amusium. Height of largest valve, 36.5; width, 36.5 ; cardinal 
margin, 19.0mm. Umbonal angle about 100°. 
Dredged living at Station 32, in 95 fms., north of Yucatan Banks, in N. Lat. 
23° 32’ and W. Lon. 88° 5’; bottom temperature not noted, but probably about 
60° F. 
Dead valves were found at Station 45, in 101 fms., bottom temperature 
61°.75 F.; at a depth of 127 fms., off Havana, by Sigsbee; and off Grenada, at 
Station 244, in 792 fms. It is probably a dweller in about 100 fms. when 
living. 
The very remarkable sculpture of this species sufficiently distinguishes it 
from any other, and specimens not fully adult may be recognized at once by 
the fimbriated basal margin of the valves. It is related to P. Philippii Récluz 
