72 STUDIES ON THE ELASMOBRANCH SKELETON, 



of the skeleton in the Selachoidei. There was an absence, 

 however, in the material at his disposal, rich though it was, of 

 certain southern forms of some little importance ; and a study 

 of some of those has enabled me to observe several points of some 

 theoretical interest. The following is the list of the species 

 examined : — 



Heptauchus indicus Complete skeleton. 



Heterodontus (Cestracion) Phillipi ... do. 



Carcbarodon Rondeletii do. 



Crossorhinus barbatus do. 



Cheiloscyllium furvum do. 



Squatina angel us do. 



Pristiophorus cirratus do. 



Trygonorhina fasciata do. 



Trygon pastinaca do. 



Urolophus testaceus do. 



Hypnos subniger do. 



Galeus canis dried skull. 



Scy Ilium stellarius do. 



Lamna cornubica do. 



Scymnus circaeensis do. 



Mustelus laevis do. 



Zygaena malleus do. 



The skeletons of the Australian species were all examined in the 

 fresh state, and the drawings made from them (with the aid of the 

 camera and sometimes of photographs), while in that state or after 

 preservation in glycerine jelly after Prof. T. J. Parker's method, 

 so that little or no distortion or alteration had taken place. 



One of the principal objects which I have had in view has been 

 to ascertain how far a comparison of all parts of the skeleton would 

 bear out the deductions as to the affinities of the various groups, 

 based by Hasse* on the structure of the vertebra?; and I have 

 added at the close of the paper a synopsis of the anatomical 

 characters of the skeleton in the principal sub-divisions, showing 

 how far this has been carried out. 



* Morphologisches Jahrbuch, II., III., IV., andSupp. to IV. 



