The Embryology of Heterodontus japonicus 667 



Text-figure 7- 



Dorsal view of the 795'mm. male specimen of Heterodontus phillipi shown, in lateral view, in Text-figure 6. 



The external openings of the spiracles are shown in the dark band crossing the head. 



After Maclay and Macleay, 1879, Fig. 3, pi. 22. 



flexed condition. The color pattern is not shown. The external spiracular opening is 

 unusually large. It does not seem necessary to reproduce this figure. 



In the order of historical sequence, the next authentic drawings of Heterodontus 

 phillipi that have come to my attention are those of Maclay and Macleay (1879). Text- 

 figure 6 is a copy of their drawing of an adult male specimen in lateral view. This is 

 probably the best drawing of an adult male Port Jackson shark ever published. One 

 should notice particularly the large head and the color pattern of the head and body. 

 The authors state that the skin is roughly shagreened, and that the color in the fresh 

 specimen is reddish'brown above and yellow with a pinkish tinge beneath. The color 

 pattern (made up of brownish'black stripes) becomes indistinct within a few hours after 

 death and in this drawing of a preserved specimen the color pattern is represented as seen 

 in perfectly fresh specimens. In addition, the authors portray a dorsal view of the same 

 adult specimen (my Text-figure 7). One is impressed by the breadth of the head including 

 the branchial region. The color pattern of the dorsal surface is decidedly more complex 

 than that of the lateral surface. The authors state that the average si2,e of adult specimens 

 of the Port Jackson Shark of both sexes is a little over three feet and that they seldom, if 

 ever, attain a length of four feet. The external reproductive organs of an adult male are 

 represented by Maclay and Macleay (1879) in their Figs. 24 and 25, pi. 24. Each 

 myoxpterygium is armed with a sharp spine. 



Of particular interest are Maclay and Macleay's figures (1879) showing lateral and 

 dorsal views (my Text-figures 8 and 9) of a very young specimen only 225 mm. (8.8 inches) 

 long. The authors state that this specimen was probably hatched only a day or two previ- 



