42 THE PLAGIOSTOMIA. 



Rhincodon typus. 



Rhincodon typus A. Smith, 1829, Zool. journ., 4, p. 443. 



Rhinodon typicus MvLLER & Henle, 1841, Plagios., p. 77, pi. 35, f. 2; A.Smith, 1849, Afr. Pisces, 



pi. 26; DuMERiL, 1865, Elasm., p. 428; Gunth., 1870, Cat. fishes Brit, mus., 8, p. 396; Halt, 1883, 



Ann. mag. nat. hist., ser. 5, 12, p. 48; Thurston, 1884, Bull. 1 Madras mus., pi. 3A; Regan, 1908, 



Proc. Zool. soc. Lond., p. 353; GiJNTHER, 1910, Siidsee fische, 3, p. 486. 

 Micristodus pimdaius Gill, 1865, Proc. Acad. nat. sci. Phil., p. 177; Jordan & Gilbert, 1883, Bull. 



16, U. S. nat. mus., p. 32; Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 52. 

 Rhinodon pentelineatus Kishinouye, 1901, Zool. anz., p. 694. 

 Rhincodon typicus Jord. & Fowler, 1903, Proc. U. S. nat. mus., 26, p. 626. 



A very large species, attaining a length of more than 30 feet, with feeding 

 habits resembling those of the basking shark, Cetorhinus. Head depressed; 

 snout broad, sub truncate; body cavity more than half the total length. Eye 

 small, lateral, near the angle of the mouth, lower lid without a fold. Spiracle 

 small, behind the eye. Nostrils at the end of the snout, near the lip; anterior 

 valves widely separated, reaching the teeth, without cirri. Mouth wide, anterior, 

 transverse, with labial folds on both jaws; upper fold elongate, lower short. 

 No longitudinal symphyseal groove. Teeth very small, subconical, sharp, 

 numerous. In the type the teeth were said to be 12 to 15 in a longitudinal row 

 and about 250 in a transverse series; Kishinouye, 1901, counted on his specimen 

 16 to 30 in a longitudinal row and 300 or more in a transverse series. Gill 

 apertures very wide, hindmost narrower, hindmost two above the pectoral. 

 Gill arches with long rakers serving as strainers for small prey. A pair of keels 

 or ridges on each flank beginning above the gill apertures, the upper continued 

 to the space between the dorsals, the lower meeting the keel at the side of the 

 tail. Pectorals large, broad, falciform with sharp angles and concave hind 

 margin. Dorsals unequal, hinder angles produced; anterior dorsal large, 

 posterior margin deeply concave, nearly in the mid total length. Second 

 dorsal small, distant from first more than length of base of latter. Anal smaller 

 than second dorsal and originating below the hinder half of its base. Ventrals 

 small, origin below hinder portion of first dorsal base. Tail with keel at each 

 side of pedicel; with notch at origin of fin. Caudal large, vertebral section 

 raised, subcaudal lobe well developed. 



Purplish to reddish brown profusely sprinkled with small spots and streaks 

 of white; lower surfaces light reddish brown. 



Cape Good Hope; Japan; Knights Key, Fla. 



