484 The American Naturalist. [May, 
Pelomedusidz has been derived. In the Sternothzeridz (Pelomedusa, 
Sternothzrus) there is no trace of a suture between intercentrum and the 
centrum of the atlas. If the sutures of the atlas in Peltocephalus or 
Erymnochelys would disappear, we would have the conditions of the 
Sternotheride. | Erymnochelys and Peltocephalus agree with all 
known Pleurodira in the fact that the centrum of the atlas supports 
the neuroids; a condition never seen in the Cryptodira or Chilotz 
(Tronychia). (Baur, Ann. and Mag. Nat. Hist., July, 1889).—G. 
Note on the Genera Hydraspis and Rhinemys.—Boulenger 
accepts in his catalogue of Tortoises the genera Hydraspis and 
Rhinemys. His genus Hydraspis contains seven species, A. hélarit, 
H. tuberosa, H. geoffroyana, H. gibba, H. radiolata, H. rufipes, H. 
wagleri. 
His genus Rhinemys contains one species, 2A. nasuta. 
Rhinemys is characterized: Neural plates present ; parietal bones 
not expanded superiorly ; parieto-squamosal arch very slender, 
Hydraspis: Neural plates present; parietal bones expanded su- 
periorly ; parieto-squamosal arch strong. 
The question is; first, can the name Hydraspis be adopted ; aud 
second, is Hydraspis generically different from Rhinemys, Boulenger, 
non Wagl. 
1. Can the name Hydraspis be adopted ? 
In 1811 Oppel! separated Æmys longicollis from Emys as a ‘‘ sub- 
genus,’’ for which he gave the following diagnosis ; Collo longissimo, 
subtestam arcuate reflexo, non fetractili; e.g., Æ /ongicollis, without 
creating a new name 
In 1828 Fitzinger ? established Chelodina for ‘‘ Emys longicollis und 
consorten.” The type of Chelodina is therefore Æmys longicollis 
Shaw. 
Two years latter Bell? established the genus Hydraspis, with nine 
species (p. 512), Testudo longicollis, which I consider the type; 7 
galeata of Schoepff, T. planiceps Schoepff, Emys amazonica, E. viridis, 
E. depressa, E. macrocephala, E. tracaxa, E. rufipes Spix. 
Later on (p. 515) we find Hydraspis : sp. typ. H. galeata (Testudo 
galeata Auct.) It is quite evident that Bell's Hydraspis is simply a 
synonym of Fitzinger’s Chelodina, and has no right to existence. 
1 Oppel, Michael, Die Ordnungen, Familien and Gattungen der Reptilien. Miinchen, 
III, 
2 Peige, L. J. Neue Klassification der Reptilien, Wien, 1826. 
3 Zool. Journ., II., 1828. 
