On the floloti/pe o/ Scalpellum angustnm. G57 



the most complete s|)eritneti from the Englisli Chalk. Only 

 one other Arcoscalpellid is known so complete as tliis, and 

 this is an example of the same species from the Chalk of 

 Mendon, P'rance, first described and figured by Ilebert 

 (1H54, Bull. Soc. geol. France, 2" ser. torn. xi. p. 470, 

 figs. 1-3) as Scalpellum darvitil, and later (1855, Mem. Soc. 

 geol. France, 2*" ser. torn. v. p. 356, pi. xxviii. fig. 1) as 

 Scaljiellum (jallicum. That specimen has just as many valves 

 as Dr. lilackinore'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 (PI. 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. AH these valves are in 

 their natural position, except that the inframedian latus is 

 pushed slightly upwards and over the rostral latus. Seven 

 or eight peduncle-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 sliglitly 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 dis[)laced 

 rostrum. 



Dr. Blackmore has not only carefully exposed all the 

 plates as seen in the figure, but he has removed all the clialk, 

 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 

 angustura (Dixo7i). By Thomas H. Withers, F.G.S. 



[Plate X. figs. 7, 8.] 



(Publielied by permission of the Trustees of the British Museum.) 



Dixon (1850, Geol. Sussex, p. 353, pi. xxviii. fig. 9) 

 established the species Xiphidium angustum on a single 

 small carinal valve from the Chalk of Sussex. 



Darwin, in his Monograpli (1851, Palaont. Soc. Monogr. 



