IJIO* { Prof. F. M'Coy on some new Cretaceous Crustacea. 



on each side by the deep lunate hollows_, or little fossae pro- 

 duced by the attachment of the posterior gastric muscles ; 

 posteinor cardiac or intestinal region not distinctly defined 

 from the branchial regions, which latter have a small curved 

 elevated elongation, bordering the inner anterior angle. All 

 these contorted lobe-like elevations on the anterior half of the 

 carapace are very minutely granular, edged by a single row of 

 slightly larger granules, and separated by broad, deep, smooth, 

 concave furrows; the posterior half of the carapace is uni- 

 formly minutely granular. Average length I inch 2 lines, 

 proportional greatest width y^^ (often larger). 



This very beautiful and distinct species is larger and flatter 

 than the others of the genus, and destitute of the tubercles with 

 which their carapace is marked, by which character, as well as 

 the very curious, slightly elevated, map-like, contorted, lobular 

 markings of the anterior half of the carapace, it is easily distil^ 

 guished from its congeners. It is comparatively rare, scarcely a'^ 

 dozen specimens having been found, while nearly a hundred 

 have been found of the iV. Mantelli (M'Coy). .,J3 



Upper greensand of Cambridge. ij;o 



(CoU. Mr. Carter, Cambridge.) ^>xiJ oldi/ob 



- - . -- .-.....-. uj oouqii'iiJO 



-38noo bn.B Jie^c* Reussia (M'Coy), n. g. - sifj mo'i'l 



Gen. Char. Small : carapace moderately tumid ; transversely 

 elliptical, front very strongly rounded; anterior lateral mar- 

 gins obtuse ; orbits of moderate size, broad, oval, approximate : 

 most of the regions of the carapace sharply defined by narrow 



/sulci; meso-gastric lobe triangular behind, abruptly narrowed 

 'to a linear tongue- shaped extension in front, reaching to the 



'^jpoint of the obtusely angular rostrum, where its apex is 



'. ifanked by two small oval swellings, indicating the anterior 



^' gastric lobes ] proto-gastric lobes large, slightly defined on 

 their outer margin; posterior gastric lobes united into one 



, transversely oblong space, slightly wider than the base of the 



''meso-gastric lobe, flanked at its posterior corners by the two 



lunate fossae of the posterior gastric muscles ; uro-gastric and 



cardiac regions undefined, tumid ; posterior branchial regions 



much depressed; anterior branchial or epibranchial lobe or 



,' region triangular, tumid, corresponding with the lateral angle, 

 find greatest width of the carapace, and defined between the 

 narrow sharply-marked linear nuchal furrow, and an oblique 

 meso -branchial sulcus, extending from about its middle to a 

 little below the lateral angle of the carapace ; meso -branchial 

 regions narrow, strongly depressed in their posterior half; he- 

 patic regions veiy large, evenly tumid; pterygostomian regions 



