158 Mr. J. W. Salter on new Fossil Crustacea 



having the carapace broad behind and narrowed in front. It is 

 the largest of all the British species, yet probably inferior in size 

 to the great Ceratiocaris (Leptocheles) bohemicus of Barrande * 

 or the C. Dewii (Onchus, Hall, Palaeontology New York, vol. ii. 

 pi. 71). It must have measured a foot when extended. One 

 large and fine specimen, presented to the Museum of Practical 

 Geology by Mr. Alfred Marston, has all the parts in situ, and, 

 besides showing the toothed jaws, enables us to connect the 

 numerous scattered relics of the species, and to restore to them 

 the tail-spines figured by Prof. M'Coy. Strictly speaking, the 

 name leptodactylus is inapplicable to tail-spines, though appro- 

 priate enough when these were regarded as the chelae of a Limu- 

 loid Crustacean. But the advantage of a more accurate name 

 cannot compensate for the introduction of a synonym ; and Prof. 

 M/Coy deserves our best thanks for his suggestive notes on this 

 and the previous species. One of his figures, referred to P. lep- 

 todactylus, belongs to the next species. 



6. C. robustus, n. sp. 



Ptei*ygotus (Leptocheles) leptodactylus, M'Coy, /. c. (in part), 

 pi. 1 E. figs. 7 c, d only (one of the lateral appendages). 



C. modicus. Telson 2^-unciale, crassum, costatum, nisi ad basin con- 

 vexum (haud gibbosum) Isevigatum. Costee in dorso tres tubercu- 

 losse, infra 4-5 Iseves. Appendices latse, lanceolatse, planse, acutse. 



The rows of lateral tubercles found on the telson of several 

 species are particularly conspicuous in this ; but they are raised 

 (not sunk) tubercles along the outer costae in C. robustus ; and 

 neither they nor the central rib run up upon the convex base. 

 The under side has several ribs. The lateral appendages are 

 remarkably broad and flat, and reach about three-fourths the 

 length of the central one. Some specimens (Lower Ludlow 

 rock) have the points of the telson more attenuated. These 

 may be males, or they may indicate a separate variety. The 

 spines in this rather striking species are remarkably thick and 

 broad. 



Loc. Ludlow (in Upper Ludlow rock) ; in the cabinet of 

 R. Lightbody, Esq. Leintwardine, in Lower Ludlow rock. 



7. C. decorus. 

 Phillips, Mem. Geol. Survey, vol. ii. pt. 2. pi. 30. fig. 5. 



Very little is known of the species represented by this frag- 

 ment. It appears nearly smooth and few-ribbed. 



Loc. Ludlow rock of Freshwater East, Pembrokeshire. 



* Not yet published. M. Barrande has, however, sent several of his 

 beautiful plates to England. 



