Yol. 54.] THE DECAPOD CRUSTACEA OP ENGLAJ;rD. 25 



In Gault specimens the marginal processes and the areolar 

 tubercles are more or less pointed, but in Greensand examples they 

 are obtuse. Specimens having the branchial region on one or both 

 sides rendered tumid by parasitic infestation are of frequent 

 occurrence. 



Additional Localities. — Lower Chalk, Dover (British Museum, 

 No. I, 2011). Gault of Puttenham (Woodwardian Museum). 

 Upper Greensand of Lyme Regis. 



Genus Eucorystes, Bell. 

 Edcortstes Broderipii (Mantell). 



1863. Palceocori/stes Broderipii, Bell, Monogr. pt. ii, p. 14 & pi. ii, figs. 8-13. 



Supplementary. — The armature of the an tero -lateral border 

 varies considerably in degree of development, the processes being 

 prolonged in some specimens into acute spines. The chelae re- 

 semble those of E. Carteri, but are larger and the fingers are 

 relatively longer. The hand is about as wide as long ; the dorsum 

 smooth; both borders have a few teeth ; the outer border of the 

 >dactylopodite is flat and has marginal ridges, that on the palmar 

 edge being toothed. Carpopodite tuberculate or spinulose. Bell 

 has described the ambulatory legs as ' nearly cylindrical ' ; but speci- 

 mens in my own and other collections show them to be of large 

 size and much compressed, both borders being sharply spinulose. 



Length of carapace ^ 19 to 38 mm. 



Remarks. — The characters which Bell assigned to his genus Euco- 

 .rystes apply so precisely to E. Broderipii that I do not hesitate, not- 

 withstanding the remarks of that experienced author, to transfer this 

 species from the genus Falceocorystes to Eucorystes. The specific 

 alliance between E. Carteri and E. Broderipii is very close. The 

 feature which especially distinguishes them is the series of singular 

 ligulate markings which occur on the cephalic area of E. Carteri, 

 but are entirely absent in E. Broderipii. The orbito-frontal border 

 is relatively narrower, but in other characters the two species 

 correspond so precisely as even to suggest the probability that they 

 may be local varieties of the same form, characterized by the 

 difference of surface-features. 



Distribution.— ~E. Broderipii is peculiar to the Gault. Specimens 

 are in the British Museum, the Museum of Practical Geology, the 

 Woodwardian and York Museums, and my own collection. 



Eucorystes Carteri (M'Coy). 



1863. Bell, Monogr. pt. ii, p. 17, pi. ii, figs. 14-17 & pi. xi, fig. 16. 

 Supplementary. — Rostrum bifid or rendered trifid by a prolonga- 

 tion of the slender process of the mesogastric lobe. Orbito-frontal 

 border equal to two-thirds the length of the carapace. In many 

 specimens the cervical sulcus is interrupted in the middle — the 

 lateral portions terminating at minute puncta between the meso- 

 and urogastric lobes. Mesogastric lobe divided posteriorly into 

 two lobules. Buccal opening rather narrow in front ; sides slightly 



