Om svenska silurcirripeder 



9 



heinta den allmänna beskrifningen ur utländsk källa, och tillåter jag mig derföre här 

 citera Olaekes arbete »The structure of certain paleozoic barnacles» 1 , från hvilket 

 också de i fig. 1 och 2 å vår tari. I återgifna afbildningarne lånats 2 . Clarke 

 skrifver (1. c, p. 139) följande: 



»The genus Lc.pidocoleus was introduced by Charles L. Faber* for a cirripede 

 from the Hudson River rocks at Cincinnati. According to Mr. Faber's identification 

 the species upon which the genus is based is that described from isolated plates 

 by Hall and Whitfield as Plumulites jamesi f . The Cincinnati specimen is appa- 

 rently entire and shows very distinctly the points of structure upon which the 

 generic diagnosis is based. The fossil consists of but two vertical rows of plates 

 and these are so arranged as to exclude the possibility of any additional accessory 

 rows. These plates have reversed symmetry and corresponding ones are of the 

 same size, but each is decidedly unsymmetrical in itself. The apices are situated 

 at one edge (which Mr. Faber has accurately termed the dorsal edge) of the flat 

 body and thus those of the two rows lie in close apposition. From this apex there 

 is a very short slope on the narrow dorsal surface and a very long slope over 

 the side to the ventral edge. The fine ornamental lines are concentric to the apex 

 and thus increase the appearence of asymmetry in the plate. The plates in each 

 of the two series overlap each other for one-half or two-thirds of their length so 

 that but a narrow portion of each is exposed. The members of the two rows alter- 

 nate with regularity at the dorsal edge so that the individual plates do not occupy 

 symmetrical positions, each being a little further forward than that most closely 

 adjoining it on the opposite row. On the dorsal edge the elevation of the apex is 

 continued into a slight thickening or ridging of the ante-lateral slope of each plate. 

 The plates of the two series come together in direct apposition without overlap on 

 the ventral edge. The resultant form of the fossil is, hence, elongate blade-shaped, 

 with broad sides, a narrow dorsal and sharp linear ventral edge. Faber's specimen 

 also shows a strong flexion of the three or four basal ] »lates toward the ventral 

 side. The autor gives no details of the structure at the distal, apical extremity 

 and the figures indicate that the specimen is broken at this point». 



* Journ. Cincinnati Soc. Nat. Hist., p. 14, pl. 1, figs A— F; 1887. 



t Palreont. Ohio, vol. 2, p. 106, pi. 4, ligs 1, 2. 



1 Clarkes här citerade arbete beskrifves äfven ett i Niagara shales anträffadt 

 synnerligen fullständigt exemplar af Lepidocoleus Sarlei Clarke n. sp. Enär der 

 lemnade artbeskrifning i någon mån kompletterar nyss anförda släktkarakteristik, 

 tillåta vi oss att derur framhålla följande detaljer. Under det att såväl höger- som 

 venstersidan — dorsahanden tankes vänd mot åskådaren — i öfriga delen visar 

 en serie likartade fjäll, bildas apicala delen af tvänne triangulära fjäll, af hvilka 

 högersidans, caudalfjället, delvis omslutes af vensteisidans något bredare terminala 



' Clarke, J. M. The American Geologist, Vol. 17 (1896). Minneapolis, Minn. 



2 Å taflan till ett mig af författaren benäget tillsändt separat finnes antecknadt: The figures 

 on this plate are upside down. Vår tafia I återger figurerna rätt vanda. 



Lunds Universitets Årsskrift. N. F. Afd. 2. Bd 11. 2 



