ME. E. E. "WATTE ON THE EGG-CASES OF SHAEKS. 325 



On tlie Egg-cases of some Port Jackson Sliarks. By Edgar 

 E. Waite, E.L.S., Zoologist, Australian Museum, Sydney. 



[Read 20th June, 1895.] 



(Plate XII.) 



The Cestracions are of special interest in consequence of the 

 vast antiquity of the family. Not only are they allied to 

 Plagiostomes the remains of which exist in Palseozoic formations, 

 but in the person of a living genus they date backwards to the 

 Chalk, where they were associated, as they now are in Port 

 Jackson, with the ancient mollusc Trigonia. 



Five living species are known : these are : — Cestracion Philijjpi, 

 Schneider, C. zebra, Gray, C. japonicus, Maclay and Macleay, 

 C.francisci, Girard, and G. galeatus, Giinther. In one species 

 only — the first named — has any description or figure of the egg- 

 case been published *. The original illustrations, being doubt- 

 less drawn from dry and distorted examples, are not very good, 

 and from these later figures have been copied with their conse- 

 quent errors. 



Few particulars have been recorded as to the situations in 

 which the living egg is usually laid, and but little definite in- 

 formation supplied as to the object of its peculiar form. Possess- 

 ing facilities not possible to many investigators, I have collected 

 what information I could, and have also been able to describe 

 the hitherto unrecorded egg-case of our second species, C. 

 galeatus. 



The living eggs of Port Jackson Sharks are most abundant in 

 spring (August and September), but are to be obtained through- 

 out the summer. Empty cases are cast up on the beaches at 

 all seasons, more especially after stormy weather. They are as 

 common on the shores of New South Wales as are the sea-purses, 

 or egg-cases of Dog-fishes, on English shores. 



Last September (1894), Mr. Cecil "W. Darley brought to me a 

 living egg. The case was unlike any I had previously seen ; 

 from each of the basal terminations proceeded a very long fila- 

 ment, similar to those attached to the egg-cases of Dog-fishes 

 {ScyUiuin). On making inquiries I discovered that such a con- 

 dition was but little known, and it was suggested to me that this 



* Cf. Dumeril, Hist. Nat. Poiss. pi. 8. 



