ON TWO NEW ELASMO BRANCH FISHES. 



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13. On two new Elasmobranch Fishes (CrossorJiinus juras- 

 sii'as, sp. nov., and ProtoSpinax annectans, gen. et sp. 

 nov.) from the Upper Jurassic Lithographic Stone of 

 Bavaria. By Arthur Smith Woodward, LL.D., 

 F.B.S., V.P.Z.S. 



[Received May 23, 1918 : Read June 11, 1918.] 

 (Plate I.) 



Most of the modern groups of Elasmobranch fishes seem to 

 have arisen during the Cretaceous period, but some are of still 

 older date, and a few interesting types are represented by well- 

 preserved fossils in the Upper Jurassic lithographic stone of 

 Bavaria, Wiirtemberg, and France. Two remarkable new 

 examples of these early forerunners of the existing fauna have 

 lately been identified in the British Museum, one apparently 

 indistinguishable from an existing genus, Crossorhivus (or Orecto- 

 lobus), the other evidently of a new genus and family closely 

 related to the Spinacidaa. 



Family CROSSOK1IINI l),E. 



CllOSSORHINUS jurassicus, sp. 11. (PI. I. fig. 1.) 



Specific Characters. — Head gently rounded in front ; length of 

 head and trunk about equal to that of the tail. Three pairs of 

 fringing dermal lappets, all undivided, the first extending along 

 the sides of the front half of the head, the next pair diminutive, 

 and the third pair largest, extending along the sides of the 

 branchial region. Pectoral fins rounded, relatively large, ex- 

 tending nearly as far back as the origin of the pelvic fins, which 

 are also rounded and about tw T o-thirds as wide as the pectorals. 

 Dorsal fins rather small and apparently nearly equal in size ; the 

 first dorsal arising opposite the hinder limit of the pelvic fins, the 

 second ending in advance of the much smaller anal fin, which is 

 close to the lower lobe of the caudal. Body and fins covered with 

 very fine shagreen, of which some granules between the pectoral 

 fins have a fluted sculpture. 



Description of Type Specimen. — The fossil, which is shown of 

 the natural size in PI. I. fig. 1, is exposed in its anterior half 

 from below, in its caudal half from the side. The snout is short 

 and bluntly rounded, and the rami of the jaws are vaguely seen, 

 meeting in an acute angle at the symphysis, where there are 

 remains of a cluster of very slender, smooth, pointed teeth. The 

 branchial region is relatively long, but the branchial arches are even 

 more obscured by the crushed shagreen than 'the ja ws. A single 



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