2 H. B. POLLARD. 



my study of the head in this group. Being, however, engaged on 

 Polypterus, I did not actively investigate their anatomy till October, 

 1891. After Christmas of that year Professor Wiedersheim procured 

 for me more material, through the kindness of Dr. Giinther, of the 

 British Museum, and Professor Mobius, of Berlin, and I Avrote a short 

 paper on their lateral 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 fish. At Naples, however, I 

 also dissected 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 Silurus glanis from a valuable series of sections, which 

 Professor 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 University 

 College, London, where Professor 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 renewed 

 a research scholarship. To the late Professor Milnes Marshall I owe a 

 specimen of Protopterus, and to Mr. Hoyle, Keeper of the Manchester 

 Museum, the opportunity of making a preparation of Geratodus. 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 biscutatus Geoffr., Cameroons. ' 



Tricliomycterus temds (Pygidium tenue) Weyenbergh, Sierra de 

 Cordoba. 



Callichtliys palealus Jenyns, Porto Alegre. 



Silurus glanis. 



A small specimen of Chaetostomus guairensis Steind., Caracas, was 

 unfitted for modelling;. 



