FOSSIL CIRRIPEDES. 533 . 



condition. These specimens are also exactly half the size of 

 Darwin's figures, which are enlarged to two diameters, and in 

 these circumstances there seems little doubt that they are the 

 original valves figured by Darwin. The carina, since Darwin 

 considered it to be the typical valve of Scalpellum, is consequently 

 regarded as the holotype. 



Two specimens in the British Museum (Natural History) add 

 considerably to our knowledge of this species. 



One, registered (I. 13577), text-fig. 65, (?, first appeared to 

 consist of a carina with fragments of the scuta and terga. Careful 

 clearing away of the matrix and the abundance of gum which 

 covered the specimen showed, however, that several of the valves 

 of the capitulum were preserved. These consist of the carina, the 

 paired scuta, the paired tei-ga, an upper latus, a rostral latus, and 

 the rostrum. The left side of the capitulum is uppermost, and the 

 carina is so exposed that the intraparietes can readily be seen. 

 Portions of the inner surfaces of the right scutum and tergum are 

 also exposed owing to the fact that the upper valves are somewhat 

 displaced and broken. 



The second specimen (I. 13580) has not so many valves pre- 

 served and those present are somewhat broken. The light side is 

 uppermost, and the plates shown are the carina, the pair of 

 terga, the upper portion of the left scutum showing its inner 

 surface, and the left upper latus. This last valve showed only its 

 inner surface, but on removal from the matrix it was found to 

 be the left upper latus. This specimen is of interest since it 

 furnished eighteen scales of the peduncle. A supposed shell- 

 fragment was removed from between the two terga, and on being 

 cleaned was found to be a peduncle scale. On removing and 

 washing the remaining matrix from the same position, the 

 number of scales was increased to eighteen. There is little 

 doubt that these scales belong to S. arouatum, since it is the only 

 species of Scalpellum known to occur in the Gault. Moreover, 

 they are ridged like the valves of the capitulum of that species, 

 and the fact that they were found in such close association is 

 prwia facie evidence that they belonged to the same individual, and 

 were washed into the position in which they were found. They are 

 somewhat similar in shape to the scales of the peduncle of the 

 Upper Senonian species ^S*. maximum and S. fossida as figured by 

 Th. Marsson *, but are easily distinguishable from them by their 

 longitudinal ridging. 



Diagnosis. — Capitulum composed probably of fourteen valves f, 

 which are ornamented with numerous fine ridges radiating 

 from their apices ; umbo of all valves apical. Carina with 

 tectum flatly arched transversely, parietes rectangularly inflected, 



* Th. Marsson, 18S0, " Die Cirripedien und Ostracoden der weissen Schreibkreide 

 der Tiisel Riigen," Mittli. natuvwiss. Vereiue Neu-Voi'pomineni und Kiigen, xii, 

 pi. i. figs. 2 6, c, d, Sd, e. 



t It is possible that this species had a subcarina, in which case the number of 

 valves would be fifteen. A higher number of valves is not likely. 



