1867.] Zoology and Animal Physiology? 135 



compartments; the whole of them can also be emptied simul- 

 taneously with a syphon. 



The trough, therefore, need not be moved when it has to be 

 filled or emptied. The zincs, which are loose, rest on the carbons, 

 which project for this purpose at their base ; and the effect of 

 removing one, or more, is not to stop, but only to diminish, the 

 intensity of the current. The cement which is most recommended, 

 is one consisting of sulphur, rendered less brittle by a mixture of 

 tar and lampblack. 



12. ZOOLOGY AND ANIMAL PHYSIOLOGY. 



Morphology. 



The Skull. — The expression " theory of the skull and vertebrate 

 skeleton," which is now very frequently used, certainly requires a little 

 explanation before the ordinary mind can perceive the meaning it 

 is intended to convey. When a theory of the origin of species is 

 spoken of, we clearly understand what is meant, for we are accus- 

 tomed to discuss theories of the origin of various other things, 

 besides species ; but a " theory of the skull " may relate to its 

 origin, to its use, or to any one of its functions. Mr. Harry Seeley, 

 in a very clever paper on this subject, prefaces his remarks by 

 stating that by a theory of the skull, he means a way of presenting 

 a set of well-known facts, so that they explain themselves. This 

 is really what is meant by Professor Owen when he advances his 

 theory of the skull, and by Professor Huxley when he advances his. 

 Mr. Seeley puts forward a view of the facts known concerning the 

 vertebrate skull, which causes these facts to explain themselves in a 

 way which does not impugn the fundamental truth of the views of 

 either of the two great comparative anatomists, but is in a certain 

 way an attempt to find the truth which lives in both, and is an 

 exceedingly ingenious and interesting essay. 



The final conclusion of Mr. Seeley 's theory is, — " That the skull 

 is the terminal segment of the body, and that just as the adjacent 

 segments consist of the pharynx, the larynx, and a vertebra 

 enclosing part of the neural column, so also the skull, which is the 

 termination of these three organs, and where their outlets are 

 visible, must consist of them also ; that the brain-case, therefore, (the 

 termination of the neural system), is a modified vertebra, that the 

 bronchial circle of nasal and palatine bones is a modification of the 

 trachea, and that the lower jaw is a modified rib developed by the 

 mouth. The respiratory circle of bones is the key to the skull." 



Races of Men. — M. de Quatrefages has brought out a work on 

 anthropology, entitled, ' Oceanic Races : the Polynesians and their 



