On the Holotype of Scalpellum angustum. 657 
the most complete specimen from the English Chalk. Only 
one other Arcoscalpellid is known so complete as this, and 
this is an example of the same species from the Chalk of 
Mendon, France, first described and figured by Hébert 
(1854, Bull. Soc. géol. France, 2° ser. tom. xi. p. 470, 
figs. 1-3) as Scalpellum darwini, and later (1855, Mém. Soc. 
géol. France, 2° ser. tom. v. p. 356, pl. xxviii. fig. 1) as 
Scalpellum gallicum, That specimen has just as many valves 
as Dr. Blackmore’s example, for, while the rostrum is missing, 
there is a sub-carina. ‘Taken together these two specimens 
show that the species had a capitulum consisting of fifteen 
valves, a like number to that deduced from a study of the 
isolated valves. 
The specimen (Pl. X. fig. 6) has the left side upper- 
most and shows the carina (apex broken), scutum, tergum 
(apical part broken), upper latus, carinal latus, infra- 
median latus, and rostral latus. All these valves are in 
their natural position, except that the inframedian latus is 
pushed slightly upwards and over the rostral latus. Seven 
or eight pedunecle-plates are present at the base of the 
capitulum; the uppermost three appear to retain their 
mutual relation, though pushed on to the inframedian latus. 
Below the peduncle-plates is seen the displaced rostral latus 
of the right side, showing its inner surface. The scutum of 
the right side is slightly displaced and its ad-occludent 
portion appears from beneath the edge of the left scutum, 
and inside this part of the right scutum rests the displaced 
rostrum. 
- Dr. Blackinore has not only carefully exposed all the 
plates as seen in the figure, but he has removed all the chalk, 
except for three pinnacles on which the capitulum rests, so 
that it is possible to examine the valves of the right side. 
Much skill has been shown by Dr. Blackmore in the 
development of this fine fossil, and it is an exceedingly valu- 
able addition to the National Collection. 
LXXIX.—The Holotype of the Cirripede Scalpellum 
angustum (Dizon). By Tuomas H. Wiruers, F.G.S. 
[Plate X. figs. 7, 8.] 
(Published by permission of the Trustees of the British Museum.) 
Dixon (1850, Geol. Sussex, p. 353, pl. xxviii. fig. 9) 
established the species Xiphidium angustum on a single 
small carinal valve from the Chalk of Sussex. 
Darwin, in his Monograph (1851, Paleeont. Soc. Monogr. 
