294 Mr. A. S. Woodward on a 



ever family Pleuroplax be placed, the type species of Helodus 

 must follow. The difficulty in associating the two genera is 

 stated by Woodward to be that " in all known examples of 

 the last-named genus {Pleuroplax) all the teeth are described 

 as fused into plates, while in the typical Helodus no such 

 arrangement has been discovered." This difficulty is removed 

 by the discovery of the examples now figured. 



EXPLANATION OF PLATE XIII. 



Fig. 1. Anterior portion of body with head of Pleuroplax, showing posi- 

 tion of month with teeth in situ, nat. size. 



Fig. 1 a. Front view of the same specimen, exposed on margin of slab. 



Fig. 1 b. Teeth from the median portion of the upper and lower jaw in 

 juxtaposition, enlarged 4 diani. 



Formation and Locality. Shale under the Drumgray Coal, Airdrie. 

 Ex Coll. Rankine Collection, University Museum, Glasgow. 



Fig. 2. Group of teeth of Pleuroplax. 



Fig. 2 a. Large posterior tooth, enlarged 2 diam. 



Fig. 2 b. A second example, also from posterior part of jaw, X 2 diam. 



Fig. 2 c. External and lateral aspect of a median tooth, with the former 



magnified 2 diam. 

 Fig. 2 d. External and surface aspects of a median tooth, X 2 diam. 

 Fig. 2 e. A tootli with deep root, x 3 diam. 

 Fig. 2/. Side view of a tootli similar to fig. 2c, X 3 diam. 

 Fig. 2 g. An example of a more elongated or attenuated tooth, X 3 diam. 

 Fig. 2 It. Tooth with a prominent crown; the lateral extension of the 



base greatly prolonged on one side, very short on the opposite 



one, X 3 diam. 



Formation and Locality. Black-band Ironstone, Airdrie. 

 Ex Coll. James Thomson, Esq., F.G.S. ; private collection. 



XLI. — Evidence of a Fossil Tunny from the Coralline 

 Crag. By A. Smith Woodwaed, F.G.S., F.Z.S. 



M. Raymond Stobms, of Brussels, who has long been en- 

 gaged in studying the osteology of the Scomberoid Fishes, 

 has lately published * some interesting observations on the 

 vertebral column of the typical genera of that family, resulting 

 in the determination of a series of large fossil vertebrae from 

 the Scaldisian Pliocene formation in the neighbourhood of 

 Antwerp. These fossils indicate a fish of very large size, 

 and agree precisely with the corresponding vertebras of 



* E. Storms, " Sur la presence d'un Poisson du genre Thymms dans 

 les Depots Pliocenes des Environs dAnvers," Bull. Soc. Beige Geol., 

 Paleont., Hydrol., vol. iii. (1889), pp. 163-178, pi. vii. 



