CHO^DKOSTEID^. 
23 
L. G. de Koninck, Quart. Journ. Geol. Soc. vol. xix. (1863), p. IT, 
pi. viii. figs. 6, 7. 
The teeth from the Muschelkalk of Jena named Thelodus injlexus 
by E. E. Schmid (Joe. cit. 1861, p. 27, pb iv. figs. 17-19) are also 
very doubtfully placed here. Nothing is known of those from 
Laineck recorded as SauricJithys semistriatus, Miinster, in E. Braun, 
Yerzeichn. Beyreuth befindl. Petrefact. (1840), p. 73. 
A fragmentary fossil from the Lower Lias of Barrow-on-Soar, * > 
Leicestershire, now in the Leicester Museum, has been provisionally jr 
associated with Belonorhynchus and SauricJithys , under the name of 
Browneichthys ornatus (A. S. Moodward, Geol. Mag. [3] voi.'*vi.. (\ 
1889, p. 455). The bones of the head are invested with ganoine -£_*<. 
and ornamented with large tuberculations. The notochord seems 
to have been persistent. At least the front portion of the trunk is 
covered with thin, deeply overlapping scales, oval or round in shape, 
with prominent concentric lines of growth, and externall) orna¬ 
mented with large ganoine tubercles. There was also a partial or 
continuous armature of the dorsal and ventral margins, consisting 
of large, narrow, pointed ridge-scales, ftto./^&J ((* j fr / 
Family CHONDBOSTEIDiE. 
Trunk elongate-fusiform; tail heterocercal. Head-bones well- 
developed, those of the cranial roof forming a continuous shield, 
without a median longitudinal series of azygous elements ; snout 
prominent and eye far forwards ; no premaxilla ; dentition rudi¬ 
mentary or absent; operculum and suboperculum present, with a 
few well-developed branchiostegal rays. Squamation rudimentary 
or absent on the trunk, robust on the upper caudal lobe. 
Only one definable genus of this family, Chondrosteus , has hitherto 
been discovered; but it seems probable that the fragmentarily- 
known genus G-yrosteus will prove to be correctly placed here. 
Genus CHONDROSTEUS, Egerton. 
C. *4V/'/ 
[Phil. Trans. 1858^p. 871 (ex Agassiz, MS.).] 
External bones feebly ornamented with granulations, partly 
coated with ganoine ; mandibular suspensorium very oblique ; jaws 
toothless; maxilla arched, much expanded behind and tapering in 
front, without process for palatine articulation; suboperculum 
large and quadrate, operculum relatively small and triangular. 
Bibs absent. Fin-rays covered with a very thin film of ganoine, 
the pectorals also sparsely granulated; all closely articulated except 
a few anterior pectorals, which are not enlarged; fulcra absent, 
