90 
NATURAL HISTORY. (Fossils.) 
[north 
Among the fossil species belonging to the family of the Chcetodons, 
(Case 20, middle,) all from Monte Bolca, and more recent tertiary form- 
ations, may be particularized the very perfect specimen (with counter- 
part) of that most singular fish, the Semiophorus velifer, from the above 
locality ; and a series of those well-known osseous bodies found in the 
crag of Norfolk, which, when cut and polished, have the appearance of 
marbled pebbles, but are recognised by Agassiz as interapophysal bones 
of a species of Platax called P. Woodwardi. 
The family of Pleuronects (Case 20, middle) is represented by one 
genus only, namely Rhombus , having one fossil species, the elegant R. 
minimus , smaller than any of the recent species, from Monte Bolca : 
the specimen here preserved was presented, together with those of the 
Semiophorus, by Chambers Hall, Esq. 
The last family of this order, the Mugiloids, (Case 20, upper shelves,) 
to which belongs the genus Mugil , with only one species, M. princeps, 
from the tertiary formation of Aix, in Provence ; and, perhaps, also the 
Calamopleurus cylindricus, from the chalk of Brazil, which, having 
only slightly crenulated scales, appear to form a passage into 
The fourth Order, the Cycloid Fishes, (so denominated from the 
orbicular or elliptic form of the scales, consisting of corneous layers, 
and having their posterior margin entire,) is subdivided into the 
Acanthopierygian Cycloids , with the following families: — the Scom- 
beroids, Sphyre&noids, Labroids, Blennioids, Loplieoids ; and the 
Malacopterygian Cycloids, comprising the families of Cyprinoids, 
Cyprinodons, Esocids, Halecoids, and Anguilliform fishes. None of 
them have representatives in formations prior to the chalk. 
Among the most ancient of the family of Scomberoids, Cuv., (Cases 
21, 22,) are the species of the genera Palceorhynchum , Palimphyes , 
Archceus, Isurus, and Anenchelum, in the slate of Glaris, of which 
a suite of characteristic specimens is here deposited ; the chalk of 
Lewes has furnished instructive specimens exhibiting the dentition of 
Pnchodus halocyon. Among those from Monte Bolca, the more promi- 
nent are the Thynnus propterygius , the Orcynus elongatus , the 
Carangopsis dorsalis, the Gasteronemus rhombus., &c. ; the heads, &c., 
of a species of Cybium, from Sheppey, from which latter locality are 
also some species of Tetrapterus r a genus of the family of Xiphoids. 
( Case 23, middle shelves. ) 
Of the family of Sphyrcenoids, (Case 23, middle,) the genera depo- 
sited are mostly known only by portions of the jaws and teeth, which 
were formerly mistaken for bones of reptiles ; such as those of the dif- 
ferent species of Saurocephalus described and figured in M. Agassiz’s 
great work, where also are to be found several delineations from speci- 
mens forming part of the series of Hypsodon Lewesiensis , which is now 
referred to a family distinct from the Sphyrsenoids, namely the Scombro- 
esocids of Muller. (Case 24, middle.) 
All species belonging to the family of the Cyprinoids or Carps, 
(Cases 24, 25,) are fresh- water fishes. The most interesting of those 
here deposited are the large and most perfect specimens of Tinea 
furcata and T. leptosoma, and another species, from the slate of Oenin- 
gen, which is also the locality from which one of the smaller species of 
Leuciscus derives its name ; the largest species of the latter genus, 
L. Hartmanni, is from the tertiary formation of Steinheim, in Wiirtem- 
