556 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
from the same locality have the adipose fin preserved. He therefore considered 
that the genus was not a good one, and, along with Osmerus, he rejected them, 
replacing the genera by those of Sardinius and Sardinoides, and placing them 
in the section of the family of the Clupeidz, which is characterized by the absence 
of sternal ribs. 
MM. Pictet and Humbert (‘‘ Nouvelles recherches sur les Poissons Fossiles 
du Mont Liban.,” 1866, p. 77) are not sufficiently clear as to the value of the 
new genus of M. von der Marck, and consider that by the law of priority the 
names applied by M. Agassiz ought to be retained. 
From a consideration of the statement of M. von der Marck, that he failed 
to find an adipose dorsal fin, and the fact that no evidence of such a fin can be 
traced in the specimens from Mount Lebanon, it may be reasonably inferred 
that M. Agassiz was mistaken when stating that traces of this fin had been found, 
and as it was principally on its presence that he relied in placing the genus 
Osmeroides amongst the Salmonida, it will be necessary to reconsider its relation- 
ship. The anatomical structure in most respects is closely assimilated with that 
of the Clupeide so far as the trunk is concerned, but the form of the head 
is different; the number of interneural spines and the extent of the dorsal fin 
in Osmeroides is much larger and more extensive than in the Clupeide; and 
the absence of sternal ribs in the former also serves to distinguish the two. 
The spinal column in the species of Osmeroides, which are described in the 
succeeding pages of this work, consists of a considerably larger number of 
vertebre than the spinal column of the species described by Professor Agassiz 
from Westphalia. The latter possess, according to the author named, Osmeroides 
microcephalus, thirty-two, and O. monasterii, at least twenty-six. 
M. von der Marck, in a description of the same fishes, but, as before stated, 
placed in a new genus (Sardinoides), states that Sardinoides microcephalus has 
twenty-seven to thirty vertebra, whilst S. monasterii possesses thirty; and two 
new species named S. crassicaudatus and S. tenuicaudatus have respectively, the 
former twenty-seven, and the latter thirty vertebre. The species, Osmeroides 
megapterus, described by M. Pictet, is designated as possessing thirty-four 
vertebr; but the example figured is a very imperfect one, and in several 
specimens which are now before me there are fifty-seven to sixty vertebre 
visible. Other species described further on possess an average of sixty; and 
in one species there are eighty-five vertebrz included in the spinal column. This 
great difference, along with those previously named, appears to indicate that the 
species obtained from the chalk of Westphalia ought to be removed from the 
genus Osmeroides, and the determination of M. von der Marck confirmed. At 
the same time there appears every probability that the third species, described 
by Professor Agassiz as Osmeroides lewesiensis (Salmo lewesiensis, Mantell., 
“Geology of Sussex”), forms the type of the genus Osmeroides. Its head is 
