656 On an Example of Scalpellum fossula. 
the length of LZ. graye. L. sarlei, J. M. Clarke, from 
the Niagara Shales (Silurian) of Rochester, New York, 
has thirteen plates to a complete shell, but this measures as 
much as 23 mm. JL. graye would seem to be more nearly 
related to L. squamatulus (Barrande), from the Ordovician 
of Bohemia, and LZ. swecicus, Moberg, from the Upper Ordo- 
vician of Sweden—two species that appear to be very close 
indeed to each other. No shell approaching completeness 
is known of the two latter species, although a number of 
plates of L. suecicus have been found in association, but the 
plates would appear to be in many instances longer in pro- 
portion to their breadth than is the case in L. graye, and the 
growth-ridges number from 8-9 to a millimetre, but with 
no intervening and almost equally prominent ridges as in 
L. graye. 
LXXVIII.— An exceptionally complete Example of the 
Cirripede Scalpellum fossula, Darwin. By Tuomas H. 
Wirners, F.G.S. 
[Plate X. fig. 6.] 
(Published by permission of the ‘Trustees of the British Museum.) 
Some years ago (1911, Geol. Mag. dec. v. vol. viii. p. 21), 
when describing certain Cirripedes in the collection of 
Dr. H. P. Blackmore, F.G.S., I mentioned that he had a 
beautiful example of the species Scalpellum (Arcoscalpellum) 
fossula, well worthy of description. Owing to its fragile 
nature, however, it was dangerous to risk sending this 
important fossil through the post, but since Dr. Blackmore 
has recently very generously presented it to the Geological 
Department of the British Museum (Registered In. 21559), 
it is now possible to proceed with its description and illus- 
tration. 
While detached valves of this species are fairly common 
in the Upper Senonian, it is quite exceptional to find the 
valves in their natural association. Darwin (1851, Pal. 
Soc. Monogr. Foss. Lepadidee, p. 24) described two speci- 
mens from the Chalk (Belemnitella mucronata-zone) of 
Norwich, each with four valves in position, one specimen 
consisting of the carina, scutum, tergum, and upper latus, 
and the other of a carina, scutum, tergum, and carinal latus. 
Dr. Blackmore’s example from the Chalk (Actinocamax 
quadratus-zone) of Kast Harnham, near Salisbury, Wilts, 
consisting as it does of fourteen valves in the capitulum, 
together with some of the plates of the peduncle, is by far 
