Louis Dollo—On the Humerus of Euclastes. 263 
the humerus of Huclastes is of the type of that of Chelydra and not 
of that of Chelone. 
VI.—Nevertheless, we shall remark that, although being more 
chelydroid than chelonoid as a whole, the humerus of Huclastes ; 
1. By its curvature less sigmoid and its flatter form ; 
2. By its head slightly less oblique on the greatest axis of the 
distal end ; 
3. By its lateral process less elevated, slightly more detached from 
the head, and less distinctly perpendicular to the surface on which 
the orifice of the ectepicondylar foramen is situated ; 
4. By its condyles less developed and slightly more displaced 
mesially ; 
5. By its more marked ectepicondyle ; 
6. By the presence of an ectepicondylar foramen ; 
differs slightly from the type of Chelydra and shows an approxima- 
tion towards Chelone. 
The foregoing considerations prove, evidently, that, if the limbs 
of Euclastes were infinitely less adapted to aquatic life than those of 
Chelone, they were, however, more so than those of Chelydra and 
perhaps even than those of Trionyx.1 But we shall return to this 
subject further on. 
VIl.—Does the humerus referred to Euclastes Gosseleti, Dollo, 
belong really to that Turtle? I think so; because: 
1. The fossil Vertebrates of the Erquelinnes sandpits were sent 
to the Museum of Brussels in separate parcels containing bones im- 
bedded in sand. Tach parcel included the remains of one specimen. 
Now, we have got two humeri appertaining to the same side (there- 
fore from distinct individuals), and each of them came in its own 
parcel containing exclusively bones of Huclastes; I shall also add 
that they were sent at different times ; 
2. The humeri agree in size with the accompanying skeletons ; 
3. They are also in the same state of fossilization, they have the 
same aspect ; 
4. If they should not be admitted to belong to Euclastes, taking 
into consideration the Chelonian fauna of Erquelinnes, there would 
only remain to look upon them as Trionyx ; but: ; 
A. They are of too large a size to have appertained to the skeletons 
of Trionyx of which carapaces have as yet been found at Erquelinnes ; 
B. They are also too dark in colour ; 
C. They offer besides differences from Triony« in the general form, 
the head, the lateral process, the intertubercular fossa, the condyles, 
the ectepicondyle, and the presence of an ectepicondylar foramen ; 
5. Moreover, Huclastes is so abundant at Erquelinnes compara- 
tively with other Chelonians (certainly 10 to 1 with respect to 
Trionyx) that: 
A. If the humeri had been found isolated, which is not the case ; 
1 On account of the distal extremity of the humerus, and the metapodials (or 
phalanges) which seem devoid of condyles, as has already been observed by Mr. E. D. 
Cope (Lertiary Vertebrata, etc., p. 111), and as I have also noticed (L. Dollo, 
Euclastes, etc., loc. cit.). 
