The Embryology of Heterodontus japonicus 



675 



for an upper jaw is 36; for a lower jaw, 33. Second, I have noted that, in the figures of 

 various authors, there is a slight difference in the shape of the opposed surfaces of upper 

 and lower jaws : in the lower jaw this surface is a trifle shorter. This may account for the 

 diiference in the number of rows of teeth. Third, in every case recorded the upper jaw 

 has more rows of anterior (cuspidate) teeth than the lower jaw. 



HErERODOHTUS ZEBRA GRAY 



This species ranges from the coasts of China and (rarely) Japan, to the East Indies. 

 It was first described in 1831 by Gray, who named it Centracion zebra. In 1851 he adopted 

 the name Heterodontus for the genus. 



The earliest drawings of this species that I have been able to find are those of 

 Maclay and Macleay (1886). These were made from a preserved specimen, a young 

 female about 518 mm. (20.4 inches) long, captured at Swatow in the South China Sea. 



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Text-figure 15. 

 A male specimen of Heterodontus zebra Gray, about 1220 mm. (48 inches) long. 



From a drawing in color by Ito, 1931, Fig. 6, pi. V. 



The color pattern is more adequately shown in my Text-figure 15, from a folio volume 

 entitled "Illustrations of Japanese Aquatic Plants and Animals", published by the 

 Japanese Fisheries Society in 1931. This represents an adult male about 1220 mm. (48 

 inches) long. The Japanese common name is said to be ''Simanekozame". 



The most conspicuous peculiarity of this species is the presence of numerous narrow 

 transverse dark-brown stripes (Text-figure 15) which suggested the specific name, zebra. 

 Except in a few places, these dark-brown stripes alternate with lighter-brown narrower 

 ones. Garman (1913) states that in a 19'inch female specimen studied by him, the body 

 and head are more slender, the head more pointed and the fins longer, than in other species 

 of the genus. Maclay and Macleay 's drawing of a dorsal view of their specimen shows 

 head and body very narrow as compared with other species. In this drawing the head is 

 rotated slightly, so the width cannot be measured for comparison with the total length. 

 Maclay and Macleay 's figures show prominent supraorbital ridges in both lateral and 



