referred to the Cirripedia. 117 



Hkrcolepas, 1 gen. nov. (Fig. 3, p. 114.) 



Sessile barnacles, in which the shell is composed of ten subtriangular 

 plates, the five inner plates sculptured with fine punctse, the five 

 outer plates about one-third smaller, longitudinally grooved, over- 

 lapping on each side the plates of the inner series, with three rows of 

 alternating plates encircling the base and consisting of an inner row 

 of smooth scales, followed by a row of rudimentary spines, and an 

 outer row of comparatively long grooved spines. 



Genotype. — Pollicipes signatus, Aurivillius. 



Aurivillius has given a very careful and detailed description of 

 Pollicipes signatus, and in the absence of an examination of the 

 specimen 1 do not propose to attempt any redescription of it here. 

 In the figure seven large plates are' seen, the three inner plates, 

 counting from the left, being called the scutum, tergum, and carina, 

 while the four outer plates are called the rostrum, lateral, and two 

 carino-lateral plates. Those of the inner series are apparently all of 

 the same shape; their outer surface is covered with minute punctse, 

 and they have an apico-basal ridge. Those of the outer series are 

 altogether differentin appearance, for they are about one-third smaller, 

 and with the exception of the rostrum which has more, the plates 

 have three longitudinal grooves with transverse ridges, the rest of 

 the plate standing out as broad longitudinal folds. As Aurivillius 

 has pointed out, the ornament resembles somewhat that of the 

 Cretaceous Pollicipes cancellatus, Marsson ( = Brachylepas naissanti, 

 Hebert sp., see Gteol. Mag., July and August, 1912). In Brachy- 

 lepas, however, the rostrum and carina have a similar external 

 ornament, as is the case in all Cirripedes with which I am acquainted 

 among either sessile or pedunculate forms ; but, if we are to believe 

 Aurivillius' interpretation of the valves in P. signatus, the rostrum 

 and carina not only differ greatly in ornament and structure, but 

 belong to different series. It may be impossible to see in the 

 specimen any characters that would guide us in determining which 

 •valves are homologous with the scuta, terga, and carina, etc., in other 

 Cirripedes, but it might have helped to give a better idea as to the 

 identity of the valves and their disposition if a view of the specimen 

 from above had been given. At present I am not satisfied with the 

 identification of the valves as given by Aurivillius. 



Hercolepas, Protobalanus, and Palceocreusia, appear to be the only 

 Palaeozoic forms that can be referred with any justification to the 

 Cirripedia. Hercolepas is an xmdoubted Cirripede, and while there 

 is very little doubt with regard to Protolalanus, there is more 

 doubt in the case of Palceocreusia. However this may be, it is of 

 interest to note that all these are sessile forms. "With the exception 

 of the supposed attachment scars of Balani recorded by Charles Moore 

 (Quart. Journ. Geol. Soc, vol. xxvi, p. 243, 1870), on shells from 

 "Wollumbilla, Queensland, and the problematic ' Balanus carbonarius' 

 of Petzholdt (see p. 113) from the Carboniferous rocks near Dresden, 

 Saxony, no other record of a sessile Cirripede is known until the 

 Upper Cretaceous. 



1 epicos = an enclosing fence. 



