366 
NAUTILOIDEA. 
of allocating them with described genera of Cephalopods. The 
result is far from satisfactory. A few arbitrary and by no means 
clearly defined genera have been established, to which a number of 
more or less widely differing “ species ” have been referred. The 
most ambitious attempt in this connection was made by d'Orbigny 
who began a monograph of the Rhyncholites ; but after describing 
several species (see list, infra, p. 375) his work was stopped, — 
plates and figures being referred to which were never published 
nor are the dimensions of the specimens given in the descriptions, 
whereby the species might have been identified. 
Pictet and de Loriol ’ adopted d'Orbigny's genus U1i}jnchoteuihU, 
and described and figured three species, admitting, however, that 
two of them might have been different mandibles from the same 
mouth. They remark that the bed in which they occur contains a 
great number of the beaks they describe, associated with the 
remains of Relemnites. In the ‘Terrain Cretace de Saintc-Croix ’ ‘ 
Pictet and Campichc, after describing a new species of Wiifn- 
choieuthis (7f. quinquecarinatus, see infra, j). 368), give a catalogue 
of the Cretaceous species of that genus, with brief descrijdions of 
each species. These are embodied in my list (see infra, p. 374). 
TRI.VSSIC. 
The Collection contains many excellent specimens of the uj»pcr 
and lower mandibles of Teninocheilns bidormfuK from Uermany and 
Prance. These have not been figured here because they have been 
thoroughly illustrated in some of the older ])aloconfological works, 
such as Munster’s ‘ Beitriige zur Petrefactenkunde ’ (Heft i. 1S43, 
Taf. V.), and BroniTs ‘ Letha?a Geognostica ’ (1837, Band i. Taf. xi. 
fig. 17, a-c). 
It is singular that (with one exception recorded by Roemer) no 
beaks should have been found in the Carboniferous rocks, in which 
the shells of IS’autiloids are so abundant. 
Horizon. Muschelkalk. 
Localities. Baireuth, Laineck (near Baireuth), Bavaria ; Luneville 
(Meurthe-et-Moselle ), Prance. 
^ Mollusques vivants et fossiles, vol. i. 1845, p. 587. 
^ Pictet and de Loriol — Description cles Fossiles contenus dans le Terrain 
Neocomien cles Voirons (Pal. Suisse, ser. ii. 1), 1858, p. 35. 
3 Descrip, des Poss. Terr. !Neocom. cles Voirons (Pal. Suisse, ser. ii. 1), 1858, 
p. 34. 
^ Pal. Suisse, ser. hi. 1862, p. 162. 
