330 THE PROCEEDINGS OF THE LINNEAN SOCIETY 



Fig. 4 (pi. 22). — Ventral aspect. (The black line, drawn with 

 the pen, on the lower part of the body, between the abdomen and 

 the anus, and the anal fin is an unnatural representation of the 

 slightly depressed mesial line.) 



Fig. 8 (pi. 23). — Lateral view of the same. 



Fig. 9 (pi. 23.) — Head of a young H. PhilUpi, about 761 mm. 

 (22-1 in.) in length, drawn from a fresh specimen (with the aid 

 of the camera lucida and compasses). 



Fig. 10 (pi. 23). — Anterior part of the head of the same 

 young fresh specimen viewed from the ventral aspect. 



[After looking at fig. 10, compare it with fig. 29 (pi. 25) in 

 order to obtain a correct idea of the nasal grooves with both their 

 orifices.] 



Figs. 11, 12, 13 (pi. 23) represent three profile-views of the 

 mouth of the same (761 mm. or 22*1 in. long) H. PhilUpi. 



Fig. 11 (pi. 23).— Mouth closed. 



Fig. 12 (pi. 23).— Mouth half open. 



Fig. 13 (pi. 23). — Mouth open to its utmost extent. 



PLATE 24. 



Heterodontus Phillipi, JBl. 



Figs. 14 and 15. — Teeth of the upper and lower jaws of the 

 young H. Phillipi, figured on plates 22 and 23 (figs. 1, 2, 8.) 



The sketch, of about five times the natural size, was made 

 from a photograph (by which the increase in size was efiected.) 

 Through the carelessness of the artist who copied the photo- 

 graph, the contours of the teeth are not at all satisfactorily ren- 

 dered. The general form of the teeth and the number of the 

 pointed cusps, however, is correct. The posterior reserve-teeth 

 of both jaws are covered by the oral mucous membrane. 



Figs. 16 and 17. — Teeth of the upper and lower jaws of an 

 adult H. Phillipi. (The preparation which formed the original 

 of these figures is in the Macleay Museum.) 



Fig. 18. — Anterior teeth of a specimen 761 mm. (22-1 in.) 

 in length, with three distinct cusps. A — those of the upper jaw ; 

 B — those of the lower. 



