90 Mr. G, B. Sowerby on Pentatrematites. 



" whilst in the P. Derbiensis it is at a very small distance from the 

 " pelvis." 



" The Pentatrematites," I am informed by Mr. Gilbertson, " are all 

 from the Calamine mines belonging to the Duke of Buccleugh, near 

 Whitwell in Bowland, on the Lancashire side of the Odder." 



Spec. 7. Pentatrematites inflata. 



P. subpyriformis, glabra. Pelvis magnus, elongatus, gradatim major. 

 A?nbulacra brevia, linearia, ad basin prominentia. 



Unquestionably very distinct from P. pyriformis, which is much more 

 nearly related to P. fiorealis; the present species has, however, nearly 

 the same shape ; it is smooth, and the pelvis is remarkably large, increas- 

 ing in thickness upwards: as far as I can judge from the only individual 

 I have seen, it consists of three plates, as in the other species. The 

 imperfect state of its preservation prevents me from ascertaining the line 

 of junction of the scapulars vdth the inter-scapulars; iho. amhidacra are 

 linear, short, and prominent, which renders it pentagonal in general form 

 when observed from above. 



" At the apex it is not perfect enough to enable us to determine 

 " whether it has five orifices, or whether it is differently formed from 

 " P. elliptica in that respect." * 



Spec. 8. Pentatrematites oblonga. 



P. oblonga; ad basin truncata, pentagonalis. Pelvis parvus, concavus. 

 Scapulares maximse, elongatge, decussatim striatse, et rugosse, fere ad 



* Upon the subject of these orifices I here add a note of Mr. Gilbertson. 

 " The five orifices at the apex have hitherto escaped observation, they are very 

 " perfectly shown in the specimens, one of them is invariably much larger 

 " than the others, in this their structure approaches the Echini; but the mark 

 " of adhesion of a column and the division of the pelvis into three pieces, con- 

 " uect them with the Crtnoidea." I however beg to refer to Vol. II. p. 313 of 

 this Journal, where it will be seen that these orifices were noticed by Say, who 

 says, " Summit with five rounded openings (ovaries)." Its name also appears 

 evidently to have been applied from that circumstance. The fact of one of the 

 five being invariably larger than the remaining four orifices had not, I believe, 

 been before observed. 



