GLYPK^A. 37 



Genus — Glyph^a, Meyer. 

 Glyph^a cretacea, M'Cot/. Plate XI, figs 11 — 13. 



Area ceplialica testae polita, septem-carinata ; carinis granulatis. 



Glyph^a cretacea, M'Coij. Ann. Nat. Hist., 1854, p. 118, pi. iv, fig. 2 ; Contrib. 



to Brit. Paleeont., p. 268, fig. 2. 



Descr. The carapace is nearly cylindrical, somewhat narrowed anteriorly ; the cephalic 

 arch nearly as long as the scapular ; the ground surface of this part smooth and polished, 

 having seven distinct carinse, which are nearly parallel, and each, with the exception of the 

 median one, formed of a single row of granulations ; the hepatic region granulated ; the 

 nuchal furrow extends almost straight across the dorsal part of the carapace, excepting a 

 slight angle forwards on the median line ; the scapular arch divided by a median longi- 

 tudinal furrow ; the regions distinct ; the cardiac region broad, polished, and sparsely 

 granulated ; the branchial uniformly more closely so, and with the lobes distinctly marked ; 

 the epibranchial small, sending forward a narrow process, which extends to the side of the 

 hepatic region ; the mesobranchial linear, narrow, and oblique ; the metabranchial very 

 broad, and very uniformly covered with granulations. The only portion of the limbs 

 which I have seen consists of the wrist and part of the hand, by which it appears that 

 the former is very small and triangular, the latter remarkably long, slightly granulated, 

 somewhat compressed, and having a very shallow, longitudinal groove near the lower 

 margin. 



Length of carapace 1'2 inch. 



It has hitherto occurred only in the Greensand at Cambridge, and all the specimens I 

 have seen are in Mr. Carter's collection. 



Ods. It is very difficult to assign with any certainty to what family of recent Crustacea 

 this genus either belongs or is more nearly related. The absence, in all the remains 

 hitherto found, of any portion of the abdomen, and, indeed, of all those parts upon which 

 naturalists usually depend for the generalisation of the species in Crustacea, precludes any 

 definite opinion on this head. The structure of the scapular arch is perfectly consistent 

 with its being an Astacoid form ; but the cephalic portion of the carapace is quite distinct 

 from any other known genus. Professor M'Coy very truly observes that there is no 

 " possible modification of Milne Edwards' nomenclature of the parts of Crustacea which 

 would enable us to describe the ridges and sulci of the gastric* region of a Glypha3a in 

 terms indicating any homology with corresponding parts in other Dccapoda.'' 



* Mr. M'Coy's word is branchial ; doubtless a slip of the pen. 



