329 



ON THE SNOUT OF A PACHYCHORMID 

 FISH {PROTOSPHYR/ENA STEBBINGI) FROM 

 THE LOWER CHALK OF S. FERRIBY, 

 LINCOLNSHIRE. 



A. SMITH WOODWARD, LL.D., F.R.S., 



British Museum. 



(Plate XIX.). 



The Cretaceous ganoid fishes of the genus Protosphyycena 

 mimic the existing sword-fishes in the outward form, and the 

 numerous species are distinguished by the shape of the elon- 

 gated snout.* Sometimes the snout is blunt (P. brevirostris) , 

 at other times slender {P. tenuis), but in nearly all cases it is 

 more or less cylindrical or oval in section. Only in one de- 

 scribed species does it form a slender flattened blade approaching 

 that of the highest sword-fishes {Xiphias), and this has hither- 

 to been known merely by two portions of a single specimen. 



Protosphyycena stehhingi, as the species with the flattened 

 blade is named, f was discovered a few years ago by Mr. 

 W. P. D. Stebbing, F.G.S., in the Lower Chalk (zone of Holaster 

 subglobosits) at Betchworth, Surrey. The parts recovered 

 were only the basal portion and a terminal fragment of a snout. 

 More recently, Mr. Thomas Sheppard, F.G.S., has obtained 

 part of a second specimen from the same geological horizon at 

 South Ferriby, Lincolnshire ; and as this belongs to a snout 

 about as large as the type, representing the part between the 

 two pieces of the latter, it completes our knowledge of this 

 interesting fossil in a very remarkable manner. 



The new specimen is shown of the natural size from above 

 (fig. i), the right side (fig. 2), below (fig. 3), and in transverse 

 sections (figs, a, b) in the accompanying plate. Combined with 

 the type, it proves that the snout measured about 45 cm. in 

 total length, which is somewhat greater than I originally 

 estimated ; and from the side view it is clear that the blade 

 curved slightly upwards towards the end like the snout of the 

 more normal species of PyotosphyycBua. 



■ As shewn by the type already described, the upper surface 

 of the base of the snout rises gently to the middle line, where 

 it is traversed by a longitudinal groove, which has a flattened 

 smooth floor and sharply-raised tuberculated edges. On either 

 side of this prominent median feature the sloping surface is 



* See especially A. S. Woodward, ' Catalogue of Fossil Fishes in the 

 British Museum,' pt. iii. (1895), pp. 399-410. 



t A. S. Woodward, ' Fossil Fishes of the Eng-lish Chalk ' (Mon. Pal. Soc„ 

 1909), p. 153, pi. xxxiii., figf. 3. 



1012 Nov. I. 



