380 R- "• POLLARD. 



ul the head in this group. Being however engaged ou PoJypterus, 

 I did not actively investigate their anatomy till October 1891. After 

 Christmas of that year Prof. Wiedkushhim procured for me more 

 material, through the kindness of Dr. Günther of the British Museum, 

 and Prof. Möbius of Berlin, and I wrote a short paper on their la- 

 teral line system, though I also investigated other parts of their 

 anatomy. Proceeding then to the Zoological Station at Naples, to 

 occupy the Oxford University table, my work on this group was again 

 interrupted, since I wished to make use of opportunities of studying 

 the development of the head in tish. At Naples however I also dis- 

 sected quite a number of the more uncommon Selachii and Teleostei, 

 and came to the conclusion that very little information could be 

 gained, as to the ancestral history of the head , from a study of its 

 development. 



Before leaving the Zoological Station I made the wax plates for 

 a model of Silunis glanis from a valuable series of sections, which 

 Prof. DOHRN, knowing how widely my views differed from his, with 

 generous magnanimity handed to me for examination. 



On my return to England I continued the present work at Uni- 

 versity College, London, where Prof. Weldon supplied me with some 

 specimens of Myxine. My study has been completed as Berkeley 

 Fellow of the Owens College, Manchester. I am also greatly indebted 

 to the Governing Body of my Oxford College, Ch. Ch., which re- 

 newed a research scholarship. To the late Prof. Milnes Marshall 

 1 owe a specimen of Protopterus^ and to Mr. Hoyle, Keeper of the 

 Manchester Museum, the opportunity of making a preparation of 

 Ceratodus. In various museums I have taken every opportunity of 

 studying fish, both recent and fossil. 



The wax models described in this paper were made from the 

 following species: 



Auchenaspis biscuiatus Geoffr., Cameroons. 



Triclwimjcterus tenuis (Pygidium tenue) Weyenbergh, Sierra de 

 Cordoba. 



Callichthys paleatus Jenyns, Porto A legre. 



Silurus glanis. 



A small specimen of Chactostotnus guairensis Stelnd., Caracas, 

 was unfitted for modelling. 



