BRANCHIAL SENSE ORGANS OF ICHTHTOPSIDA. 215 



To Professor Milnes Marshall, in whose laboratory the later 

 researches on Elasniobranchs were made, my acknowledgments are 

 due not only for the privilege of the use of his library of zoological 

 works, but also for his valuable assistance, criticism, and advice. I 

 also wish to express my best thanks to Professor Wiedersheim for 

 good counsel, and to my friend Dr. L. Will, who very kindly made a 

 number of useful extracts from Gotte's great " Unke " work, a work 

 which was inaccessible to me in Manchester. 



