292 Mr. A. S. Woodward on the 



Loc. Sandakan, N. Borneo. A single specimen obtained 

 l>y Mr. Douglas Cator. 



This species inay be at once recognized from S. sumotranus 

 ( = /S. Biccorii, Thorell, Ann. Mus. Genov. xviii.p. 25,1882) 

 i'rom Sumatra and from R javanvs (Thorell, loc. ci't. p. 30) 

 from Java by having the upper surface of the trunk smooth 

 and not densely granular. 



XXX. — A Conirihution to the Osteology of the Mesozoic Amioid 

 Fishes Caturus and Osteorachis. By A. Smith WOOD- 

 WARD, F.L.S. 



[Plates VIII.-XL] 



The well-known Leeds Collection from the Oxford Clay ot 

 Peterborough has already furnished many important illustra- 

 tions of the osteology of the Mesozoic fishes. Several more 

 examples, however, still remain to be utilized, and the present 

 contribution to our knowledge of the early Amioids is chiefly 

 based on a fine series of new specimens of Caturus and one of 

 Osteorachis in this collection. The description of these is 

 followed by a brief note on a unique example of the Liassic 

 Osteorachis v>acroc(phalus, which has hitherto been impcr- 

 f( ctly known, but can now be elucidated with greater precision. 

 The whole series of observations sl)0ws more clearly than 

 ever how extraordinarily similar are certain Mesozoic rhombic- 

 scaled notochordal genera to the existing Aynia, even in some 

 of the minute features of osteology. 



I. — Catueus, sp. ind., from the Oxford Clay of 



KORTHAMPTONSHIRE AND WILTSHIRE. 



There is still so much uncertainty as to the distinction of 

 the various species of Caturus known even by whole skeletons 

 that it seems inadvisable at present to give any speciHc names 

 to the conipaiatively iragmentary examples of this genus fiom 

 the English Oxford Clay. Their great interest consists not 

 in their precise systematic relationships, but in their naturally 

 dissected condition, which adds so much to our knowledge of 

 the osteology of the fish. It must suffice to remark that most 

 of the specimens belong to a species closely related to, if not 

 identical with, the typical Caturus furcatus of the Bavarian 

 Lithographic Stone; while some have coniparalively larger 

 and iewer teeth. All these fossils Lave now been acquired 



