HAMMER-HEADED SHARK. 507 



pupils black ; the nostrils are elongated, and open immedi- 

 ately underneath the depression, or notch, in the anterior 

 margin of the laterally expanded portions of the head ; the 

 mouth semicircular, and furnished with three, four, or five 

 rows of teeth, depending upon the age of the specimen ; these 

 teeth are large, sharp, somewhat triangular and curved, with 

 smooth cutting edges when the Shark is young, but serrated 

 afterwards ; the teeth in the upper jaw having their points 

 directed towards the angle of the mouth ; those of the lower 

 jaw have the same direction, but they are narrower. 



The body is elongated, covered with a skin slightly gra- 

 nulated ; the colour greyish brown above, nearly white be- 

 neath : branchial openings five, all before the base of the 

 pectoral fin ; the pectoral fins nearly triangular ; the first 

 dorsal fin large ; the second small, and placed just in advance 

 of the commencement of the tail ; the inferior lobe of the 

 tail small, the superior portion as long as the head of the 

 fish is wide ; the anal fin is under the second dorsal. 



This species is found in the Mediterranean, on the shores 

 of the various countries of Europe, in the Ocean, and on the 

 coast of Brazil. 



To make this subject as complete as my means will allow, 

 and afford an opportunity of identifying any other species 

 of Zygoena that might wander to our shores, I here add, 

 as a vignette, representations of the heads of the other known 

 species, of which No. 1 is Zygcena tudes, Val. the synonymes 

 being, according to M. Valenciennes, Le Squale pantouflier 

 of Lacepede, t. i. p. 260, pi. VII. fig. 3. Duhamel, sect. IX. 

 pt. ii. pi. XXI. fig. 4 to 7. Koma Sora Russel, pi. XII. 

 This species has been found in the Mediterranean, on the 

 coast of Coromandel, and at Cayenne, S. America. 



No. 2. Zygoena Tiburo, Val. syn. Squalus Tiburo, 

 Linn. torn. i. p. 899, sp. 6. Tiburonis species minor, 

 Marcg. 181. Willughby, tab. B. 9, fig. 3. Klein Misc. 



