and Systematic Position of Cheii'olepis. 239 



correctly identified by him ; but he failed to find the branchio- 

 stegal rays and the two sizes of teeth described by Agassiz. 

 But it is specially worthy of note that Pander seems to have 

 been struck by the considerable resemblance which certain 

 bones of the head of Cheirolepis bore to those shown in 

 Quenstedt's drawing of the head of Palieoniscus islehiensis 

 in the ' Handbuch der Petrcfactcnkunde.' 



The question of the systematic position of Cheirolepis was 

 next discussed by Prof. Huxley*. Unfortunately, the material 

 at his disposal at the time he wrote did not afibrd him the 

 opportunity of making much advance on what had been 

 already done by Pander, though assuredly he was on the 

 right track. He accepted the institution by Pander of a 

 distinct family of Cheirolejnni ] and as regards the suborder 

 in Avliich this family should be included, he considered that 

 it ought " perhaps to be regarded as tlie earliest known form 

 of the great suborder of Lepidosteida3." The single short 

 dorsal tin, the absence of jugular plates, and the non-lobate 

 character of the paired fins were points justly considered by 

 Prof. Huxley as excluding Cheirolepis from the Crosso- 

 pterygida3. 



In 1867; however, Mr. Powrie published a paper f in which 

 he questioned the accuracy of the data on which Prof. Huxley's 

 opinions were founded. Cheirolepis^ Mr. Powrie affirmed, 

 does possess two large principal jugular plates ; and the struc- 

 tures described by Agassiz as branchiostegal rays, but not 

 seen by Pander or Huxley, " correspond to the lateral jugular 

 plates not uncommon in Ganoid fishes.^' Although in this 

 paper Mr. Powrie thinks that Prof. Huxley's objections to 

 Cheirolepis being a Crossopterygian are so far negatived, he 

 nevertheless does not positively indicate the systematic posi- 

 tion in which he thinks it ought to be placed. 



In Dr. Liitken's essay on the Classification and Limits of 

 the Ganoids I, Cheirolepis is placed, somewhat hesitatingly, 

 among the Lepidosteids, Mr. Powrie's jugular plates proving 

 to him rather a stumbling-block. In the English absti-act of 

 this elaborate paper, Dr. Liitken states the absence of jugular 

 plates to be one of the characteristics of the group of Lepi- 

 dosteids, " with the sole exception of Cheirolepis, the only 

 Devonian fish of the whole series which indicates by its 

 gular plates a certain relationship to the contemporaneous 

 Polypteridge "§. Again, in the full German edition published 



• Dec. Geol. Survey, x. (1861) pp. 38-40. 



t Geol. Magazine, iv. 1807, pp. 147-152. 



X Vidensk. Meddelelser nat. For. Kjobenhavn, 1868. 



§ Aun. & Mag. Nat, Hist. 4th ser. vii. p. 331. 



17* 



