Correspondence. 93 
1834, Prof. Agassiz says :—‘If we estimate the number of fishes 
now known to amount to about 8,000 species, we may state that 
more than three-fourths of this number belong to two only of the 
above-mentioned orders, namely, the Cycloidians and Ctenoidians, 
whose presence has not yet been discovered in the formations inferior 
to the Chalk.’ 
Relying, no doubt, upon such high authority, eminent Paleontolo- 
gists of our own country have perpetuated that statement to the 
present time. For example, the late Dr. Mantell says, in his 
‘ Medals of Creation :’—‘ According to the data at present obtained, 
all the osseous fishes anterior to the Chalk belong to genera which 
have no representative among existing species, and they are charac- 
terized by rhomboidal scales, covered with enamel.’ These are 
therefore the scales of Ganoid fishes. 
Professor Owen, in his ‘ Paleontology,’ published as late as 1861, 
writes, page 175:—‘ Seeing that the earth yields no indisputable evi- 
dence of Ctenoids or Cycloids anterior to the Cretaceous epoch.. .’ 
From which I infer, that he has met with no information to remove 
from his mind the dictum of M. Agassiz. 
In 1852, at the meeting of the British Association at Belfast, T 
communicated my discovery of parasitic borings in fossil fish-scales 
from the Chalk formation. Soon afterwards, when pursuing similar 
researches, on examining the laminated shale of the Kimmeridge 
Clay from Ely, and also in Norfolk, I found along with small vertebrae 
and ribs unmistakable Cycloid scales, and these scales had been 
attacked by boring parasites.* Herewith I send two enlarged out- 
lines of scales from the specimen of Kimmeridge shale in my collection; 
Fig. 2. 
Fish-scales from the Kimmeridge Clay (much enlarged). 
one from a common scale (fig. 1), the other from a lateral tubular 
scale (fig. 2). The size of the common scale is 1th inch in width, 
by ith in its antero-posterior diameter. When in London this 
spring, Mr. Davies, of the British Museum, showed me a small slab 
of Kimmeridge shale, containing fish-bones and fish scales strikingly 
resembling those in my specimen. 
Prof. John Phillips, if my memory does not deceive me, informed 
me at the British Association meeting at Oxford, that he had seen 
Cycloid fish-scales in the Oxford Oolite. Accepting the above data, 
* See Trans. Micros. Society, vol. ili. pl. 1, fig. 5. 
