654 Bashford Dean Memorial Volume 



It is known that Dean, while in Japan, made extensive collections of biological 

 material other than Heterodontus, and that he was also engaged in the collection of 

 Japanese armor; but his keen interest in the embryology of Heterodontus is attested by the 

 following statements included in a letter (Dean, 1901.2, p. 85) to the Columbia University 

 Quarterly : 



My first object in visiting Japan was to secure the eggs and embryos of the Port Jackson 

 [sic] shark, a form which there is some reason to believe traces a direct descent from known 

 sharks of Carboniferous times. Its embryos, therefore, might reasonably be looked upon to 

 furnish evidence as to the relationships of the oldest sharks, and, therefore, as to the oldest 

 backboned animals. At Misaki I soon found that this form was moderately common, and the 

 native divers and fishermen finally brought me in a valuable series of its eggs. 



In his article on the embryology of Chlamydoselachus, Gudger (1940) has noted that 

 Dean collected embryos of Heterodontus and Chlamydoselachus in the same general locality 

 (though in different habitats) and simultaneously. When we consider the results of the 

 two undertakings, certain differences are very obvious: whereas for Chlamydoselachus 

 there was a scarcity of early stages and a fairly complete series of older embryos, for 

 Heterodontus nearly all stages are represented. To illustrate this, one need only compare 

 the plates illustrating the present article with those of Gudger's article on the Embryology 

 of Chlamydoselachus, No. VII in this Volume. 



Of the approximately 200 embryos of Heterodontus japonicus collected by Dean, 

 there are now, after more than 35 years, available for study only the following: (a) Six 

 embryos in a crumpled condition, preserved in alcohol. Roughly measured, these range 

 from 38 mm. to 90 mm. in length. In general, the condition of this material is as good as 

 could be expected since it has been preserved for thirty^iive or forty years, (b) A single 

 embryo about 3.5 mm. long, stained, cleared and mounted in toto on a slide, (c) Twelve 

 slides containing serial sections of seven different embryos in stages ranging from an 

 early blastula to an embryo about 10 mm. long. Several series are imperfect or very 

 incomplete, but the orientation is good and the stain (apparently borax carmine) has not 

 faded appreciably. Nevertheless, the paucity of material is such that for the embryology 

 ical portion of this article we must depend almost entirely on Dean's notes and drawings. 

 Fortunately the drawings represent not only surface views, but quite a number of embryos 

 that had been stained, cleared, and mounted whole. 



It was at Misaki that Dean made the only photograph of a fresh'caught Japanese 

 Bullhead Shark on record (my Text-figure 3, further described on page 693). This photo- 

 graph is particularly valuable since there is but one juvenile and no adult specimen of 

 Heterodontus japonicus in the American Museum at the present time. Fortunately, there 

 are available two specimens of H. quoyi, one young and the other adult or nearly so; and 

 two specimens of H. francisci, one nearly full-grown and the other undoubtedly adult. 

 The external anatomy of all these specimens is briefly described in the section on "The 

 Species of Heterodontus''\ 



