325 



NOTES ON PROSOBRANCHIATA. 



No. iv. — The Ontogenetic Stages represented by the 

 Gastropod Protoconch. 



By H. Leighton Kesteven. 



i. — Intkoduction. 

 ii. — The Ontogenetic Stages. 

 iii. — The Naticoid Initial Whorl. 

 iv. — The Systematic Value of the Protoconch. 



i. — Introduction. 



Since the publication of my paper on the *' Protoconchs of 

 certain Port Jackson Gastropoda" (3) in May, 1902, I have con- 

 tinued to devote a good deal of time to the study of these 

 interesting " monuments " of early Gastropod development; some 

 of the conclusions and results arrived at have appeared from 

 time to time in these Proceedings and in the publications of the 

 Australian Museum. The published results, however, stand for 

 but a small portion of the study that has been devoted to the 

 subject. In the execution of my duties while a member of the 

 staff of the Australian Museum, many thousands of specimens 

 passed through my hands for mounting and bestowal in their 

 places in the cabinets and cases; all these were carefully examined 

 as to their protoconchs, as was also no small portion of the large 

 collection already bestowed and arranged before my appointment. 

 Added to this, I have zealously collected material for the studj^, 

 personally in New South Wales and Queensland, and by 

 exchange from Victoria, South Australia and Tasmania. Here 

 I should like to acknowledge my indebtedness to Mr. W. T. 

 Bednall, of Adelaide, whose many consignments of rich shell 



