10 



BRITISH FOSSILS. 



JR. sesquiuhcialis (in exempl. Brit.) depressus, ovatus, glabella late urceohtd, quam longa 

 latiori, antice angustissimd ; sulcis sursum curvatiSy nec marginem attingentihm ; oculis 

 longissimis ; genis dilatatis, angulis in spinas latas extensis; ihorace segmentis 10, pleuris 

 falcatis, fere axin convexiorem cequantibuS) fulcro proximo; caudd longd, quadrispinosd, spinis 

 externis longioribus. 



M. de Barrande, ■when in England, agreed with ns in identifying this species ; and we 

 adopt the above specific name, believing it to be but common courtesy, when cor- 

 recting the mistake of a careful and judicious author, to retain the name he imposed. 

 M. de Barrande, it is true, described as a tail the reversed glabella of this species, 

 but he carefully distinguished it from all other Bohemian trilobites ; and M. Corda 

 has conferred no advantage on science in changing both the genus and species, 

 although he had fortimately obtained a perfect specimen. He has figured the eyes 

 much too short ; they curve round the glabella, and nearly meet in front, as may 

 now be well seen in the lately published figure of M. Barrande, quoted above. 



Localities. — Ehiwlas, near Bala, not unfrequent. We have specimens from Koenigshof, 

 Bohemia, in the uppermost part of the Etage D. of Barrande. 



J. W. Salter. 



August, 1853. 



