10 FOSSIL MALACOSTRACOUS CRUSTACEA. 



longitudinally divided by a furrow, outer stalk linear ; female abdomen oval, the sixth 

 segment as long as the fom-th and fifth together, the seventh triangular. 

 Length and breadth of the carapace 09 inch. 



Obs. The above description is taken from several specimens in Mr. Bowcrbank's 

 collection, and iu the British Museum. Li none of them are there any remains of the 

 limbs. In one only, a female, is the abdomen existing, and in another the body is 

 sufficiently perfect to give the form of the rostrum, and the above imperfect details of 

 the antennse, orbits and external footjaws. These data are sufiicicnt to indicate a 

 marked afiinity to several genera of the family INIaiadae, to which the fossil evidently 

 belongs ; and -whilst in some respects the structure appears to point to a near relation to 

 Miihrax, in others it appears to approximate to Libinia. 



This is the only instance known of any fossU representative of the -extensive tribe 

 of the Oxyi-hynchi ; and this circumstance renders it one of the most interesting additions 

 we have made to our knowledge of extinct Crustacea. Professor Milne Edwards has 

 the following observation on this subject.* "Jusqu' ici nous ne connaissons aucuu 

 Cmstacu fossile que Ton puisse regarder, avec quclque certitude, comme appartenant ii la 

 famille des Oxyrhinqucs." The species referred by Desmarest to the genus Inachiis, 

 is, as will be shown, a species of the Anomurous group, and is nearly aUied to Dromia. 

 It will be found described under the name of Dromilites Lamarckii, and is the 

 Basinotopus of M'Coy. It has no relation whatever, to the present family, and thus, until 

 the i)resent instance, the observation of Edwards remained unexccptioual.t 



AU the specimens known are fi-om the Isle of Sheppey. 



Sub-Order— CYCLOMETOPA. 



Family— Ck^CYMDM. 



Genus — Xantuopsis, M'Coy. 



Char. Gen. Testa ovata, supra nodosa, fronte quadrilobo. Orbito' latae, angulis 

 lateralibus et infcriore prominentibus. Fossa untennaricn ovata?, apertae. Antenna 

 externa articulo basali bis longiore quam latiore, lateribus pai-allelis : interna articulo 

 basah late triangulari, anticc truncato, ad fi-outcm attingente. Fedipalpi externi caule 



* ' Hist. Nat. des Crust.,' tome i, p. 271. 



t Since the above -was written, Mr. Woodward has pointed out to me in tlie British Museum a small 

 specimen (a Crustacean) from the Gault, which appears to belong to the Oxyrhynchi, and which would 

 constitute a second exception. I have also been favoured with two specimens from the collection of 

 M. Edwards, one from Colwcll Bay, in the Isle of Wight, the other from Brockenhurst, Hants, which may 

 possibly prove to belong to the Oxyrhynchi, but which require further examination. These will be 

 further considered at a future time. 



