RHINOBATIDJE . 
83 
Type. Complete skeleton, except hinder portion of tail. 
Snout apparently rounded and obtuse. Disk much elongated. 
Length of pectoral fin about three times its breadth at the insertion. 
Form, fy Log. Middle Eocene : Monte Bolca, near Verona. 
Rhinobatus martensii , E. Yoetling (Abh. geol. Specialk. Preussen 
u. Thfiring. Staaten, vol. vi. pt. 3 (1885), p. 31, pi. yii. fig. 1 ), is 
founded upon vertebrae from the Eocene of Samland, East Prussia. 
Other vertebrae have been described by C. Hasse from the Senonian 
of Aix-la-Chapelle 1 , the Uppermost Cretaceous of Maastricht, in 
Holland 2 , and Ciply in Belgium 3 , the Bruxellian of Etterbeck 4 , 
and Woluwe St. Lambert 5 , near Brussels, and the Molasse of Bal- 
tringen, 'Wurtemberg 6 . 
Vertebrae of Rhinobatus also occur in the Kimmeridge Clay of 
England (46332 a. Three examples from Culham, Oxford. Cunning - 
ton Coll.). 
n. 
Genus TRYGOJMORHHNTAj Mfiller & Henle. 
[Syst. Beschreib. Plagiostom. 1841, p. 124.] 
Genus differing only from Rhinobatus in having the anterior nasal 
valves confluent, and forming a broad quadrangular flap. 
Trygonorhina dezignii, J. J. Heckel, Sitzungsb. math.-nat. Cl. k. 
Akad.Wiss.Wien, vol. xi. (1854), p. 124.—-Middle Eoceno; 
__ Monte Postale, V. Italy. jjd. £ 
The following genera appear to show that, in Jurassic times, the 
Bhinobatidae and Bajidae were still less differentiated than at the 
present day. They do not precisely accord with the definition of 
either of these families. 
Genus Thiolliere. 
[Poiss. Foss. Bugey, pt. i. 1854, p. 8.] 
Tail very distinct from the disk, which is almost of rhombic 
shape. Pectoral fins not extending forwards beyond the base of the 
snout; pelvics not notched. Tail with two smooth spines upon the 
proximal half, and apparently two dorsal fins on the distal half, with¬ 
out caudal fin 7 . Body partially covered with conical dermal tubercles, 
the larger only superficially calcified. Teeth minute, smooth. 
1 Natfirl. Syst. Elasm., Besond. Theil, p. 112, pi. xiv. figs. 17-19, 
2 Ibid. pp. Ill, 116, 118. # 3 Ibil f. p. 115, pi. xy. figs. 28-31. 
4 Ibid. pp. 112, 116, 118, pi. xiv. figs. 20-26, pi. xv. figs. 32-35, 42-46. 
5 Ibid. p. 116, pi. xv. figs. 36-39. e p 
7 The known fossils do not clearly elucidate this character. 
Gr 2 
