526 Bashford Dean Memorial Voume 



Among the embryological records accumulated by Dr. Dean during these two trips 

 and left unpublished at his death, are numerous drawings showing various stages in the 

 development of the primitive shark, Chlamydoselachus. In keeping with the plan and 

 purpose of this volume, as briefly set forth by Gudger and Smith on page 49 of Article II, 

 the present contribution has been prepared in order to preserve for science these excel- 

 lent drawings. 



This article (No. VII) forms the third and last of a series dealing with this rare 

 shark. In the first, Gudger and Smith (1933) brought together from widespread sources 

 everything then known concerning the natural history of the fish, to form a background 

 for work on the anatomy and the embryology. Next came Dr. B. G. Smith's monograph on 

 the anatomy. This includes a review of the results of many investigators, but to these 

 studies. Dr. Smith added the results of his own investigations on certain organ systems 

 either wholly or partly omitted by other writers. Smith's dissections, it is interesting to 

 note, were done on specimens obtained in Japan by Dean. 



And now there are set before me two tasks. The first is to make a study of Dean's 

 notes on the breeding habits and seasons and on the structure and functioning of the re- 

 productive organs of the frilled shark. These notes are few, fragmentary and scat' 

 tered throughout a notebook marked Chlamtdoselachus and in various loose notes, 

 sketches and photographs. However, I have been able to piece together from Dean's 

 notes, from the specimens loaned from Columbia University, and from the scanty litera- 

 ture, sufficient data to extend considerably our knowledge of these subjects. I am fortu- 

 nately able to bring forward for comparison data from my observations on the breeding 

 habits and genital organs of various sharks and rays, and particularly of the nurse shark, 

 Ginglymostoma cirratum, whose reproductive habits and large shelled eggs are remarkably 

 like those of Chlamydoselachus. 



My second task is to prepare descriptions and explanations of the admirably drawn 

 figures of the eggs and embryos of this shark left unpublished by Dr. Dean at his untimely 

 death. For reasons to be given later, it will be clear why these figures do not portray 

 a completely graded series of embryos but only such stages as were procurable with great 

 difficulty. But before beginning the consideration of these drawings, other and intrc 

 ductory studies of the fish must be made. 



Almost nothing has been published about the breeding seasons and breeding habits 

 of the frilled shark and equally Httle concerning the functioning of the reproductive organs. 

 Even less is known about the development of Chlamydoselachus. But when the breeding 

 habits and seasons and the reproductive organs have been studied and the figures of the 

 embryos described, the reader will have a fair idea of the life history of the frilled shark. 



Some years before his death in 1928, Dr. Dean asked me to collaborate with him in 

 preparing an article such as this. But having much work planned for years ahead, I pre- 

 sented my case, and, Dean, generous as always, withdrew his request and urged me to 

 proceed with my own studies. And now that he is gone, I am trying to do what could 

 have been done long ago so much better in collaboration with him, since his memory 



