MAZATLAN BIVALVES 163 
on Anomia lampe, shewing the hnge.—719, 3 valves approach- 
ing O. iridescens.—720. 3 do. purple, one with the form of 
Modulus to which it had attached itself.—721, 5 do. orange 
tinted.—722, 3 do. stronger texture.—723, very young speci- 
mens on Anomia lampe, hes Vermiliz, &e.—724, do. on Cre- 
pidula and Imperator. —725, a very regular valve on Conus 
regularis.—726, a pair aa valve on living Modulus. The 
latter must have been greatly in the way of ‘the creature when 
it walked out: on coming to the extremity of the shell, it has 
turned up and waved its margin.—727, a very smooth sp. inside 
Trochus versicolor.—728, 2 finely grown large valves.—729, 2 
pairs and valves on Murex nigritus, jun., margin turned up 
and waved.—730, a pair (and valves) on Arca tuberculosa ; 
margin of both upper and lower valve very suddenly turned 
up and waved. 
Tablet 731 contains 6 valves, solid white variety, known 
from O. Columbiensis by the crenations.—732, valve on Vitu- 
laria salebrosa. —733, crowded valves on Arca tuberculosa. 
N.B. Dead valves, common on this shell, assume an ochre 
yellow colour.—734, valve on living Modulus, with deep hinge 
cavity. 
214, 6. OsTREA PP? CONCHAPHILA, var. PALMULA. 
O. 2? conchaphila, t. satis magnd, margine subito ascendente, 
valva inferiore superante, undulato, limbo purpureo seu olivaceo 
trregulariter tessellato ; lined pustularum valvd& superiore, in 
parte nacred, a murgine remota, circumeunte, in puncta convent- 
entia valvd inferiore aptante ; pagind internd subnacred, auran- 
tio seu purpureo tincta ;\ rarissine spinis ramosis paucis, tubulis 
ad marginem exteriorem arborescentibus. 
Compare Ostrea Cumingiana, Dkr. Zeit. f. Mal. 1846, p. 48. 
(Patria ignota.) 
Remarkable for the palmated foliations in the outer margin, 
which has a distinct limb mottled with purple and olive; and 
for the row of denticles within this limb and within the nacre- 
ous border, fitting into corresponding depressions in the other 
valve. Asthese seem to appear only in the adult shell, it is 
barely possible that O. conchaphila may occasionally develop 
itself into this form. Mr. Nuttall however agrees with me in 
regarding them as distinct. Long. 2°3, lat. 1°6, alt. 54. 
Hab.—Mazatlan ; extremely Tare 5 LT’pool Col.—S. W. Mexico, 
BoP: C.—Upper California, Nuttall. 
