referred to the Girripedia. 113 



•especially to point out that the occurrence in Palaeozoic times of the 

 essentially recent genera Pollicipes and Scalpellum is still unproved. 

 In a paper now in course of preparation I propose to deal in more 

 detail with the structure of Turrilepas, Plumulites, and Lepidocoleus. 



Balanus. 

 Under the name Balanus carbonarius, Petzholdt (Be Balano et 

 Calamosyringe, Additamenta ad Saxonice Palceologiam duo, 8vo, Dresdce 

 and Lipsice, 1841, p. 5, pi. i; " Uber Balanus carbonaria," Neues 

 Jahrb., p. 403, pi. iv, 1842) has described from the Carboniferous 

 rocks near Dresden, Saxony, a group of fossils which, from the 

 description and figure, it is impossible to accept as belonging to the 

 genus Balanus or even to the Cirripedia at all. Darwin (Pal. Soc. 

 Monogr. Foss. Lepadidse, 1851, p. 5) l has already pointed out that, 

 "as neither the operculum, the structure of the shell, the number of 

 the valves, nor their manner of growth, can be made out or are 

 described, the evidence appears quite insufficient to admit the 

 existence of this genus at so immensely a remote epoch." Until 

 further evidence is forthcoming we are unable to admit the Cirripede 

 nature of this fossil. 



Protobalanus, P. P. Whitfield, and Pal^oceetjsia, J. M. Clarke. 



Both these forms appear to be Cirripedes and were founded on 

 single specimens referred to the Balanidse under the name Proto- 

 balanus hamiltonensis, 2 P. P. Whitfield, from the Middle Devonian, 

 Hamilton Group (Marcellus shales) of Avon, Genessee Co., N.Y., and 

 Palceocreusia devontea, 3 J. M. Clarke, from the Middle Devonian, 

 Corniferous Limestone of Le Boy, Genessee Co., N.Y. 



Protobalanus hamiltonensis (Fig. 1, p. 114) is represented by a small 

 depressed-convex shell, ovate in general outline, narrowing towards 

 the carinal end, and composed of twelve peripheral plates. There is 

 a semicircular carina elevated above the other plates, a short rostrum, 

 and five pairs of subtriangular lateralia, which are regularly disposed 

 and symmetrical, the radial areas of the plates being conspicuous and 

 apparently smooth. The length of the specimen is 4-5 mm., and its 

 greatest breadth 3 - 5 mm. Although this form has a greater number 

 (twelve) of plates than is the case in any of the forms of the family 

 Balanidas (the number in that family being eight, six, four, or, where 

 all the plates are coalesced, one) it has certain characters in common 

 with the members of that family. In the first place it has at each 

 extremity plates comparable to the rostrum and carina, the carina as 

 usual being the highest plate, and on each side the paired lateralia, 

 which number five in Protobalanus, while the highest number in 

 a member of the Balanidae, namely Octomeris, is three. There are 

 also radial areas to the plates, but it is not clear whether all the 



1 See also Darwin, Eay Soc. Monogr. sub-class Cirripedia, Balanidoe, 1854, 

 p. 492. 



2 B. P. Whitfield, in Hall & Clarke, Palaont. Neio York, vol. vii, p. 209, 

 pi. xxxvi, fig. 23, 1888 ; E. P. Whitfield, Bull. Amer. Mus. Nat. Hist., vol. ii, 

 p. 67, pi. xiii, fig. 22, 1889. 



3 J. M. Clarke, in Hall & Clarke, Palceont. New York, vol. vii, p. 210, 

 pi. xxxvi, figs. 24-6, 1888. 



DECADE VI. — VOD. n. — NO. III. 8 



