400 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY, 
multicostatus in the collection, and many of them have about the same number of 
ribs, thirty-four, the maximum being about. forty. On a close and careful inspec- 
tion, however, certain differences appear, which lead to a doubt as to its identity. 
Theaverage specimens of G. multicustatus have the valves heavy, thescars marked 
by an elevated ridge, and almost, always have more or less dark brown on the inte- 
rior of the disk. "The radiating costae are low, flat, and polished in most cases, 
nof in any observed case sculptured, and the interspaces are narrow, shallow, and 
only crossed by incremental lines. 
In the valve above mentioned the radial costae are elevated, their upper edges 
almost overhang the channels, and the upper surface is closely transversely threaded. 
The channels without exception are elegantly reticulated by concentric, regularly 
spaced, elevated lirae, about five to a millimeter. The interior of the shell is 
pure white, the adductor scars are very little raised; there are eleven anterior 
and thirteen posterior teeth forming a continuous arch on the hinge plate. 
Whether these differences are merely individual, or whether we have to do 
with a species closely allied to but distinct from G. multicostatus, will require 
much more copious material to determine, 
(C. Isoponra.) 
Pectinacea. 
Pectinidae. 
PECTEN Mijtiur, 1776. 
Having seen somewhere a statement that the name Pecten was first used in 
a generic sense by Peter Osbeck, in his “ Voyage to the East Indies and China,” 
1765, I took the trouble to hunt up the reference (p. 391, op. cit.), and found 
that Osbeck’s name has no standing in systematic nomenclature, as no definition 
is given and no described species is referred to it. It is a nomen nudum, pure and 
simple. From the context it is evident that the name is used colloquially, as vus 
long done by the pre-Linnean collectors, for Murices of the type of Murex tenui- 
spina with a long canal having small spines at right angles to it, which among 
dealers and collectors was often called pecten-veneris, or Venus’ comb. The first 
to use Pecten in the modern sense was Rumphius, in 1704, from whom it is prob- 
able Müller derived his generic name, and who preceded Osbeck by more than 
half a century. 
PECTEN s.s. 
Pecten sericeus Hiwns. 
Pecten sericeus Hinds, Zool. Voy. Sulphur, 1844, Moll., p. 60, pl. 17, fig. 1. 
Panama Bay, 53 fathoms, Hinds. U. S. 8. * Albatross," station 3368, pes 
Cocos Island, Gulf of Panama, in 66 fathoms, rocky bottom, temperature 557.4 F. 
U.S. N. Mus. 192,804. 
