50 FOSSIL CIRRIPEDIA. 



have a different appearance from their homologues in any recent species : they are 

 trigonal, with their basal margin rounded and one end produced, to which end a narrow 

 well defined ridge runs obliquely from the apex of the valve. 



The peduncle is known only in P. concinnus ; in this species it is covered with minute 

 quadrangular calcified scales. 



f. Scuta, aiit Icevia ant lineis tenuibus incrementi solum notata. 

 A. Scuta, costd ah apice ad centrum marginis basalis non decurrente. 

 1. PoLLiciPEs Concinnus.- Plate III, fig. 1. 



PoLLiciPES CONCINNUS. J. Morris. Annals of Nat. Hist., vol. xv, 1845, p. 30, 



pi. vi, fig. 1, et Mineral Conch., pi. 647, fig. 1. 



P. scutis pane quadratis, margine hasali prope rostrum subconcavo, segmento tergo- 

 laterali, e lineis incrementi tit videtur rejtexis formato, lato, rotundato et prominente : tergis 

 latis, pane quadratis : carina margine basali, ut videtur acuto. 



Scuta, almost square, with the basal margin near the rostrum a little hollowed out ; 



tergo-lateral slip, apparently formed by upturned lines of growth, broad, rounded, and 



protuberant. Terga broad, almost square. Carina, with the basal margin apparently 



pointed. 



Oxford Clay, Middle Oolite, attached to an Ammonite. Mus. Pearce. 



Although to my great regret the state of Mr. Pearce's health has prevented him 

 allowing me to examine the specimens in his possession, yet I have thought it advisable to 

 commence the genus with this species, as it is in a far better state of preservation than any 

 other specimen hitherto discovered. We gain by a single glance the knowledge that at so 

 remote a period as the Middle oolite a true Pollicipes existed. In no other instance that I 

 have heard of, has the peduncle been perfectly preserved. Mr. Morris first named and briefly 

 described this interesting species ; subsequently Mr. James Sowerby has given enlarged 

 drawings (without any description) of it in the ' Mineral Conchology ;' and it is from these 

 figures that I have drawn up my specific description, which, from this cause, is necessarily 

 imperfect. The figures in this volume are copied from those in the ' Mineral Conchology,' 

 which I may remark have evidently been executed with great care, and Mr. Sowerby's 

 accuracy of observation is universally well known. The peduncle is several times longer 

 than the capitulum : Mr. j\Iorris describes the scales on the peduncle as being small, closely 

 pressed together, somewhat quadrate in form, and each regularly marked by a transverse 

 carinated ridge ; this latter character I do not understand. The rostrum is not clearly 

 figured by Mr. Sowerby, but I believe that I can see evidence of its existence. From 

 these materials it would appear that the P. concinnus is more nearly related to the recent 

 P. cornucopia, and its two nearest congeners, than to the other species of the genus. 



