EL0PID.15. 
11 
Genus OSMEROIDES, Agassiz 
[Poiss. Foss. vol. v. pt. ii. 1844, p. 103.] 
s .to. Rhabdolepis, W. von der Marck (non Trosohel, 1857), Palseontogr. 
vol. xi. 1863 , p. 20. 
Holcolepis, W. von der Marck, ibid. vol. xv. 1868, p. 278. 
Head and trunk not much laterally compressed, and abdomen 
flattened. Parietal bones in contact in the median line ; mandible 
*1 little prominent, and gape not extending behind the eye ; two 
s upramaxillnry bones; margin of the jaws and some inner bones 
with clusters of minute bluntly-pointed teeth, sometimes perhaps 
tntoral. Branchiostegal rays about 20 in number, about five of 
*ho uppermost and broadest supported by the cpihyal. Vertebrae 
between 50 and 70 in number, about 20 being caudal ; the centra 
uot longer than deep, all slightly constricted and marked with 
s mal] irregular longitudinal ridges. No enlarged scale at the base 
ot the paired fins ; dorsal fin never much longer than deop, opposite 
°r nearly opposite the pelvic pair; anal smaller than the dorsal fin ; 
caudal fin forked ; no fin-rays excessively elongated. .Scales often 
oi 'lamented in their exposed portion with delicate radiating lines 
°1 minute tubercles, marked in their covered portion with a few 
radiating grooves terminating in notches at the anterior truncated 
margin ; hinder margin not serrated ; course of lateral line indicated 
a feeble ridge and a notch in the hinder border of most of the 
scales. 
The generic name Osmeroides was originally given by Agassiz to 
some fishes from the Cretaceous of Westphalia catalogued below 
in the family Scopelidse ( Sardinioide/s monasteri). When it was 
afterwards applied to fossils discovered by Dr. Mantell in the 
English Chalk, Agassiz expressly stated that the determination of 
generic identity was uncertain and provisional. In course of time, 
however, the name has become universally recognised as belonging 
to the Euglish specimens, and loast confusion will be caused in 
established nomenclature if Osmeroides lewesiensis be regarded as 
the type species. 
Osmeroides lewesiensis (Mantell). 
[Text-figure 2.] 
1822. Salmo lewesiensis , G. A. Mantell, Foss. South Downs, p. 235 
pl. xxxiii. fig. 12, pi. xxxiv. fig. 3, pi. xl. fig. 1. 
l^ Th \o“ e WaS fir8t pub,i8b9d ’ with0Ut definition > by Agassiz, Neues Jahrb. 
