172 T.H. Withers — Shell-fragments described as Cirripedes. 



Mr. Linsdall Richardson states, "I have found several examples of 

 plates belonging to a species inseparable from this one [P. alatus, 

 Tate] in the Lias of oxynoti-armati hemeree that was exposed when 

 excavations were being made for a new gas-holder at the Gloucester 

 Gas Works." Mr. Richardson most kindly sent me examples of the 

 supposed Cirripede plates from that locality, and these confirm the 

 conclusion already arrived at that they, like P. alatus, merely 

 represent the right anterior ears of some form of Pecten-like shell. 



ScALPELLUir soLiDULTjM Steeustrup sp. (Text-figs. 3-6, p. 170.) 



Steenstrup (1839, Kreyer's Naturhist. Tidsskrift, Ed. ii, p. 412, 

 pi. V, figs. 14, 14*) founded this species on an, undoubted carina of 

 a Cirripede from the Chalk of Scania. Darwin, however, when 

 redescribing the species in his monograph (Pal. Soc. Monogr. Foss. 

 Lepadidse, 1851, p. 42, pi. i, figs. 8a-/), included with a carina and 

 tergum, a Pelecypod fragment (figs. 8e-/) from Kopinge, Scania, but 

 this in no way affects the nomenclature of Sealpellum soliduhim. 

 This shell-fragment (Text-fig. 3), which was considered by Darwin 

 to be a carinal-latus ^ of S. solidulum, really represents the anterior 

 ear of a right valve of a species of Pecten, 



A shell-fragment (Text-fig. 4) of the same nature from the Chalk 

 of Riigen, was figured by Marsson (1880, Mitth. naturw. Yereine 

 Neu-Vorpommern undRiigen, Jahrg. xii, p. 15, pi. i, fig. 15), and the 

 figure given of that fossil is so good, and shows its fractured inner 

 edge so well, that one can only wonder that it should have been 

 described as a Cirripede valve. 



Subsequently, IS". I. Karakasch ("Les Cirrhipedes du terrain 

 cretace de la Crimee," Trud. St. Petersb. Obsch. Estest., vol. xxxi, 

 livr. 5, p. 14, pi. i, figs. 17, 18), no doubt following Darwin and 

 Marsson, figured two similar shell-fragments (Text-figs. 5, 6) from 

 the Chalk (Upper Senonian) of Bakla, Crimea, as carinal lateral valves 

 of ScalpelUim soliduhim. These may not, however, belong to the 

 same species of Fecfen to which the shell-fragments figured by 

 Darwin and Marsson belong. 



Similar shell-fragments, which are undoubtedly the anterior ears 

 of right valves of Pectens, were included with a large number of 

 Cirripede valves in a collection of fossils sent to the Geological 

 Department of the British Museum from the Chalk of Riigen, but, as 

 in the case of those figured by Darwin, Marsson, and Karakasch, it 

 would be a very difficult and unprofitable task to attempt to determine 

 the species. 



Conclusion. 



"While the present communication may be taken as showing that 

 certain so-called Cirripedes from the Jurassic and Cretaceous Rocks 

 are really the remains of Pelecypod shells, it must not be regarded as 

 exhaustive. It deals only with those of which the originals can be 

 examined, or as to the nature of which no doubt is possible. Some 



^ In his other memoir (1851, Bay Soc. Monogr. Lepadidse, p. 245) Darwin 

 thought that he was wrong in considering this to be a carinal-latus, and that it 

 was probably an upper latus. 



