STRUCTURE AND CLASSIFICATION OF THE FOSSIL CRUSTACEA. 



321 



to the list, including the great Stylonurus Scoticus*, nearly 4 feet in 

 length. 



Of the other species we now possess much more ample material than was 

 at the disposal of Messrs. Huxley and Salter in 1859, when their Monograph 

 appeared, and many important details in the structure and position of the 

 parts and their mutual relations are now elaborated. 



In addition to the Devonian localities of Herefordshire, Forfar, Arbroath, 

 and Dundee, the Upper Silurian of Lanark, and the Lower Ludlow of Leint- 

 wardine, Shropshire, all of which have yielded new and characteristic forms 

 (several of them described by me during the past year), I have lately obtained 

 from the "Wenlock Limestone and Shale, Dudley, good evidence that in this 

 locality also species of Pterygotus occur. 



Until June 1865, the oldest known Cirripede was the Pollicipes Shceticus 

 from the Ehsetic beds of Somersetshire ; but I have just described f a new 

 Cirripede with intersecting rows of plates (similar to the Cretaceous genus 

 Loricula), from the Wenlock Limestone and shale of Dudley, figures of which 

 are addedj. 



Tukeilepas Weightii, H. Woodw. {Chiton Wrightii, De Kon.). 



Fig. 1. Specimen from Mr. E. J. Hollier's collection. 



Fig. 2. „ Mr. Charles Ketley's „ 



Fig. 3. „ Mr. H. Johnson's „ 



Figs, a, b, c represent the three forms of plates of which the several rows are composed 

 in figs. 1-3, which bear the corresponding letters. The opercular valves are not known. 



Another Cirripede of the genus Pyrgoma, occurring recent on the south 

 coast of England and Ireland, living in deep water attached to the edge of 

 the cup of Caryojohyllia, and fossil in the Coralline Crag of Suffolk, has now 

 been detected by me in the Upper Chalk of Norwich. As this is a new 

 species I have named it Pyrgoma cretacea. It is interesting to find it asso- 

 ciated with the same genus of corals (Caryophyllia) both in the Chalk and in 

 recent seas. 



I have examined and determined six genera, and am preparing descriptions 

 of about sixteen new species of Liassic Crustacea. 



* See Quart. Journ. Geol. Soc. vol. xxi. pt. 4, Nov. 1865, " On Hemiaspis" 



t See Quart. Journ. Geol. Soc. vol. xxi. pt. 4. 



X Two detached valves of this fossil were discovered by Mr. John Gray of Hagley, and 

 described as a Chiton by M. De Koninck, Bulletins de l'Acad. de J3ruxelles, 1857, 2nd 

 series, vol. iii. p. 199, pi. 1, f. 2. 



1865. z 



