96 



ON THE DEVELOPMENT OF HETERODONTUS 

 (CESTRACION) PHIL LI PI. 



Part I. 

 By Professor William A. Haswell, M.A., D.Sc. 



(Plates IV. -V.) 



During a zoological expedition undertaken in September, 1893, 

 for the purpose of exploring the marine zoology of Jervis Bay, a 

 part of the New South Wales coast to the fauna of which little 

 attention had been directed, I was struck by the unusually large 

 number of the egg-shells of Heterodontiis ( (J eatracion) which were 

 to be seen on the beaches. Most of them were old and broken, 

 usually covered with the tubes of Eupomatus; but after examining 

 a number, I succeeded in obtaining a fresh one containing an 

 egg with an early blastoderm. Eventually I found that many of 

 these were to be found at low tide sticking in the crevices of the 

 rocks, firmly wedged in by means of the spiral flange which forms 

 such a remarkable feature of the egg-shell ; and with the help of 

 of Mr. J. P. Hill, who was of the party, I succeeded in collecting 

 a considerable number. Of these as many as possible were pre- 

 served in the camp, but a large number were taken whole to 

 Sydney, and more satisfactorily dealt with in the laboratory: Mr. 

 Hill, on a second trip to the same locality, brought back a good many 

 more. Some of these were kept alive for da^'s in the laboratory. 

 The cutting of a door in the egg-shell did not seem to interfere 

 with the development, and, with proper appliances for renewing 

 or aerating the sea-water, I have little doubt that it would be 

 possible in this way to follow the course of the development for 

 a prolonged period. This I hope to be able to do with regard to 

 the later stages at some future time. The present communication 

 refers only to the stages prior to the appearance of the notochord: 

 detailed reference to the literature is deferred. I am much 



