PERMIAN FOSSILS FROM DURHAM. 287 



propose, as a more correct generic term, the name P/vsoponisciis,* 

 as suggested by a paljeontological friend. 



Though my original specimens are in no respect inferior to 

 those of Schauroth's, I did not venture to name and describe 

 them when they were first noticed, but postponed doing so in the 

 expectation of procuring more examples, and obtaining a more 

 definite knowledge of the affinities of the species. It was not, 

 however, until the summer of the present year that any further 

 traces of it were found, when one or two other fragments from a 

 different locality were met with. In all, six specimens have 

 been obtained: two from Humbleton Quarry, three from Field 

 House, Ryhope, and one from Tunstall Hill. 



Drawings of the most perfect of these have been submitted to 

 Mr. C. S. Bates, and I am indebted to that gentleman for the 

 following interesting remarks: — 



" There is but one order among recent Crustacea with which 

 figs. 1 and 2 can be identified, and that is the Isopoda. But the 

 relation of the fossil to the recent species is peculiar. In all 

 recent forms (as far as I know) where the eyes project upon the 

 surface of the integument, the cephalic region is small, being less 

 than the next succeeding segment; but this fact, which is very 

 constant in the adult animals, is not permanent in the larval 

 condition of the same; the head or cephalic segment being more 

 important in relation to the succeeding rings. But from all the 

 larval or adult forms of prominent-eyed Isoiwds this fossil speci- 

 men differs in the anterior position of the eye. This may be a 

 specific distinction only. 



" The fact that this Isopod^ found in so early a geological 

 period, assumes rather the larval than the adult form of the 

 recent type, is consonant with all we know of the relation which 

 animals generally of so early a date hold to existing species." 



We must therefore, it appears, look upon our fossil Crustacean 

 as belonging to the family Isopoda, though somewhat of an ab- 

 normal character in reference to the recent forms. 



Baron Schauroth's specimen from the Zechstcin-dolouiite of 



* Yi:ijmpi6-'<(>jn)s (Or.), a face or ma.sk. aii<l lini.-ikos (<ir.), onisciis. 



