29 
M. Von Meyer e. g. primarily divides the Order into— 
A. DIARTHRYI, with a two-jointed wing-finger. 
Ex. Pterodactylus (Ornithopterus) Lavateri. 
B. TETRARTHRI, with a four-jointed wing-finger. 
Ex. All the other known species of the order. 
These again are subdivided into— 
1. Dentirostres. Jaws armed with teeth to their ends; a bony 
sclerotic ring; scapula and coracoid not confluent with one an- 
other * ; a short moveable tail. 
Ex. Pterodactylus proper. 
2. Subulirostres. Jaws with their ends produced into an edentu- 
lous point, probably sheathed with bone; no bony sclerotic ; 
scapula and coracoid confluent ; a long and stiff tail. 
Ex. Pterodactylus (Ramphorhynchus) Gemmingi +. 
The extremity of the upper jaw of the Pterodactylus Cuvieri is 
sufficiently perfect to demonstrate that it had a pair of approximated 
alveoli close to its termination, and we may therefore refer it to the 
Dentirostral division. 
In this division, however, there are species which present such dif- 
ferent proportions of the beak, accompanied by differences in the rela- 
tive extent of the dental series, as would without doubt lead to their 
allocation in distinct genera, were they the living or recent subjects 
of the modern Erpetologist. In the Pterodactylus longirostris, the 
first species discovered and made known by Collini in 1784 ¢, the 
Jaws are of extreme length and tenuity, and the alveoli of the upper 
jaw do not extend so far back as the nostril. In the Pterodactylus 
erassirostris, Goldfuss §, on the other hand, the jaws are short, thick, 
and obtusely terminated, and the alveoli of the upper jaw reach as 
far back as the middle of the vacuity which intervenes between the 
nostril and the orbit, and which Goldfuss terms the ‘cavitas inter- 
media.’ 
In the solid or imperforate part of the upper jaw anterior to the 
nostril, the Pterodactylus longirostris has twelve long, subcompressed 
teeth, followed by a few of smaller size: the same part of the jaw 
in the Pt. crassirostris has but six teeth, of which the first four are 
close together at the end of the jaw, and the first three shorter than 
the rest. The cavitas intermedia in Pt. longirostris is much smaller 
than the nostril; in the Pt. crassirostris it is larger than the nostril. 
Were these two species of dentirostral Pterosauria to be taken, as 
by the modern Erpetologist they assuredly would, to be types of two 
* The condition of the scapular arch in the Pt. giganteus, Bow., Pt. conirostris 
mihi, demonstrates the fallacy of this character. 
t Palzontographia, Heft 1, 4to. 1846, p. 19. 
t Acta Academie Theodoro-Palatine, V. p. 58, tab. 5. 
é Beitrage zur Kenntniss verschiedener Reptilien der Vorwelt, 4to. 1831, sec. 1. 
tab. 7, 8, 9. 
