216 A. Smith Woodward — On a Second Species of Eurycormus. 



ribbed at its anterior margin ; and nothing more than part of the 

 base of the pectoral fin can be observed on the right side. The 

 scales are beautifully preserved and resemble those of the type 

 specimen. 



Specific Determination. — The length of the head in each of the 

 fishes thus imperfectly indicated w^ould be about 0*13m,, and the 

 species represented is therefore much larger than the typical E. 

 speciosus of the Bavarian Lithographic stone.^ According to the 

 original description, the last-named fish is also distinguished by the 

 smoothness of all the external bones. In size and characters the 

 head of E. Egertoni agrees much more closel}' with that of E. grandis 

 from the English Kimmeridge Clay. From this, however, it also 

 difl'ers in the remarkable rugosity of the cranial roof-bones, and 

 apparently in the greater breadth of the squamosal elements as com- 

 pared with the parietals. E. Egertoni is thus the third known species 

 of the genus. 



Formation and Locality. — Although the type specimen is said to 

 have been obtained from the " Gault " of Speeton, Yorkshire (pre- 

 sumably the Speeton Clay), the horizon cannot be determined with 

 certainty, even if the record of the locality be correct; for the fish 

 is contained in a mass of indurated clay that has been much 

 waterworn, evidently by rolling on the beach, and the matrix 

 exhibits no invertebrate fossils by which its age can be recognized. 

 The fact that it agrees exactly with the new specimen from the 

 Oxford Clay of Peterborough is almost certain proof that the original 

 E. Egertoni is not a Cretaceous, but an Upper Jurassic fossil ; and 

 the discovery of further specimens in the Yorkshire cliifs will be 

 awaited with interest for the settlement of the stratigraphical 

 question. 



EURYOORMXJS, Sp. 



Eurycormus will probably soon be recognized as having a still 

 wider range in British Upper Jurassic formations than is now 

 proved ; and it is worthy of note that certain vertebral rings and 

 hypocentra, not uncommonly met with in the Kimmeridge Clay 

 of Weymouth, are more closely paralleled by those of this genus 

 than by those of any other known fish. One such specimen (Brit. 

 Mus., No. P. 6176) was figured by Mr. Damon, ^ and there are 

 several others in the British Museum (Nos. 41181, 41231, 45926). 

 There is one detached horse-shoe-shaped hypocentrum (No. 41231a) 

 bearing a pair of pedicles (each perforated transversely by a foramen) 

 for the support of ribs ; and some of the complete rings exhibit a 

 feeble oblique line on each side, as if formed by the coalescence of 

 horse-shoe-shaped hypocentra and pleurocentra. These rings also 

 bear a small pedicle or raised facette on the lower part of each side. 



* A. 'Wagner, " Monographie der fossilen Fische aus den Lithograpliischen Schie- 

 fern Bayerns," Abh. k. bay. Akad. Wiss., math.-pbys. CI. vol. ix. (1863), p. 707, 

 pi. iv. A smaller fisb, probably to be regarded as the young of E. speciosus. is also 

 named E. dnbius by B. Vetter, Mittb. k. mineral. -geol. Mus. Dresden, pt. iv. (1881), 

 p. 113, pi. ii. fig. 7. 



' E. Damon, "Geology of "Weymoutb," ed. 2, suppl. pi. xii. fig. 9 (1880). 



