NOTES ON SOME AUSTRALIAN SHARKS. 
193 
Gill openings 15/20/20/19/13 mm. Preoral length 41, width of mouth 39, 
length of arc 22. Depth of body about 65 mm. Snout to first dorsal 170. 
First dorsal base 59, its height 80. Interdorsal 127. Second dorsal base 20, 
its height 11. Caudal peduncle 40. Upper caudal lobe rather more than 3 
times length of lower. Pectoral fin 71. Anal base 29. Anal-caudal interspace 36. 
Form elongate and tapering, the body broadest and deepest near first 
dorsal fin, if the lateral expansions of the head be excluded. Head hammer- 
shaped, the cephalic extensions sloping slightly backwards and the anterior 
margin of the head with five concave sinuations. Eye large with round pupil 
and nictitating membrane. Slit of nostril subequal to eye, valve small ; an 
anterior groove runs a short distance along each side of the profile of the 
head. Numerous sensory canals and pores on head. First and second gill 
opening more separated than the others ; the fifth is above the pectoral. 
Mouth almost semicircular, labial folds obsolescent. The teeth are erect, with 
their acute points directed outwards and number about 20 to 25 in each jaw ; 
one series in function and median teeth smallest. 
Lateral line conspicuous ; a large lunate pit above and a smaller one 
below the caudal peduncle. Scales exceedingly minute, forming a satiny shagreen. 
First dorsal elevated, arising behind vertical of pectoral base. Second 
dorsal originating over the first third of the anal whose base is one and a-half 
times as long as that of the second dorsal. Pectorals short and somewhat 
rounded. Ventrals small. Lower caudal lobe rounded ; upper notched below. 
Caudal fin about one-third of length without hammer. 
General colour, in formalin, browiiish, lighter below. The margins of 
the fins with peacock blue and greyish iridescence. 
Described and figured from the specimen recorded by Ogilby as 8. tudes, 
a female, 23 inches long. 
Locality . — Moreton Bay, Queensland. Qld. Mus. Regcl. No. I. 740. 
Distinguished from Platysqualus (Valenciennes) by the arrangement of 
the sensory organs and pores on the head 5 and by general details of proportion, 
shape, etc. 
A mask modelled after a Hammerhead Shark has been figured from 
Jervis Is., Torres Strait, by Meyer (K. Ethnogr. Mus. Dresden vii, 1889, pi. 
iii), and a shrine to this remarkable shark is mentioned in Frazer's Golden 
Bough (v, 1919, footnote 1 on page 139) from Torres Strait also. 
3 Lloyd and Sheppard, Proc. Zool. Soc. (Londcn), 1922, iv, pp. 971-98], figs. 1-7, 
give an account of Ihe anatomy of the head of a hammerhead shark. 
