4 FOSSIL MALACOSTRACOUS CRUSTACEA. 



breadth of the front, find the more even transverse direction of the nuchal farrow, indicate 

 a difference between the two forms which I consider sufficient to warrant a distinct generic 

 ])lace. 



The resemblance is still so striking in the general form of the carapace, the existence 

 of four triangular teeth on the latero-anterior margin, and the waved outline of the front, 

 that I have thought it desirable to express the similarity in the name applied to it. The 

 genus A'(7«///o itself, as it was left by Prof. Milne Edwards, requires a complete revision, 

 and ought probably to be considered as comprising three or four genera, an arrange- 

 ment which that distinguished naturalist suggests bv the sections which he has himself 

 indicated. 



X.vNTHOSiA GRANULOSA, sp., M'Col/. Plate 1, fig. 13. 



Marginc latcro-antcriore lobis quatuor obtusis. 

 Reussia granulosa, M'Co;/. 



With some hesitation I have referred the species indicated, but neither figured nor 

 described, by Prof. M'Coy, under the name of lieussia granulosa, to the present genus, 

 instead of that to which the author had assigned it. The specimens which I have had an 

 opportunity of observing are scarcely sufficient to supply me with any satisfactory 

 characters, but such as exist lead me to consider the species as more nearly allied to 

 Xanllioxia than to Jicuxxia of M'Coy. The general form of the carapace is very similar 

 to that of the foregoing species, but the latero-anterior margin, instead of having four 

 rather acute teeth, has that number of obsolete lobes; this margin also extends somewhat 

 further back than in the former. The regions are very well marked, and are even more 

 gibbous than in X. r/ibbosa. The carapace is evenly covered with minute and I'egular 

 granulations. 



Length of the carapace, 7 incli ; l)readth, Vi inch. 



It has hitherto been found only in the upper Greensaud of Cambridge, where it is 

 very rare. The specimen figured, and fron\ which the above imperfect description is 

 taken, is in Mr. Carter's collection. 



Gen us — 1 vr V L s , Ma >/ icU. 



Char. Gen. Tcxla transversim ellij)tica. bis fcrr latior quam longior, tul)erculata, 

 sulco nuchaH transverso fere recto in medio divisa. Orbilce oblongse, approximata?, supra 

 tuberculis tribus subtiis excavatis arniata'. Pcdrx longi, gracilis. 



