36 WOODWARD : FOSSIL FISHES OF THE UPPER LIAS OF WHITBY. 
it is a little emphasized by the abrasion of the outer surface. 
Beyond the origin of the dorsal fin all the scales are smooth and 
with non-serrated hinder border ; while those of some series at the 
ventral border are excessively broad compared with their depth. 
None of the head-bones or opercular plates can be distinguished. 
Ptycholepis bollensis, Agassiz. 
Plate V. 
1832. Ptycholepis bollensis, L. Agassiz, Neues Jahrb., p. 142 (name 
only). 
1833-44. L. Agassiz, Poiss. Foss., vol. ii., pt. i., 
p. 11 ; pt. ii., p. 108, pi. Iviii, h. 
1849. „ „ W. C. Williamson, Phil. Trans., 1849, 
p. 444. 
1852. „ „ F. A. Quenstedt, Handb. Petrefakt., 
p. 203, pi. XV., fig. 5. 
1858. „ „ F. A. Quenstedt, Der Jura, p. 231, 
pi. XXX., figs. 1-7, pi. xxxi., fig. 8. 
1865. „ „ G. Cotteau, Bull. Soc. Sci. Yonne, 
vol. xix., pt. ii., p. 337. 
1875. Ptycholepis barrati, H. E. Sauvage, Bibl. Ecole Hautes 
Etudes, vol. xiv.. No. 1, p. 8, pi. ii., 
fig. 2. [Distorted fish.] 
1891. „ „ H. E. Sauvage, Bull. Soc. Sci. Yonne, 
vol. xlv., pt. ii., p. 33, pi. i. 
1895. Ptycholepis bollensis, A. S. Woodward, Catal. Foss. Fishes, 
B. M., pt. iii., p. 317. 
Type: Imperfectly preserved fish from Whitby ; British Museum. 
The definition of the genus Ptycholepis, published by Agassiz, 
was based upon an imperfect fish from the Whitby Lias, now in the 
British Museum. Though the typical species, P. bollensis, to which 
the Whitby fish belongs, was originally named after Boll, the locality 
in Wiirtemberg where the first fragments were met with, this was 
the only satisfactory example which Agassiz had the opportunity of 
examining. Even this specimen, however, is so imperfect as to be 
misleading in some respects, and fossils subsequently discovered both 
