594 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 115 



The nominal subgenus Rhizoprionodon has a cu"Cumtropical dis- 

 tribution with the exception of Oceania. The subgenus Protosygaena 

 is found in the western south Atlantic and the Indo-Pacific exclusive 

 of Oceania and the coasts of Africa. 



Rhisoprionodon (Rhizoprionodon) aciitus (Riippell) 



Figures 5, 6 

 "Sorra Kowah" Russell, 1803, Descriptions and figures of two hundred fishes . . . 



Coromandel, vol. l,p. 9, fig. 15 (a common name). 

 Carcharias acutus Riippell, 1835, Fische des rothen Meeres, p. 65, pi. 18, fig. 4 



(market at Djetta; lectotype designation in Klausewdtz, 1960, Senck. Biol., 



vol. 41, nos. 5, 6, p. 292). 

 Carcharias sorrakowa Bleeker, 1853, Verh. Bataviaasch Gen., vol. 25, p. 9 



(Vizagapatam, based on "Sorra Kowah" Russell; see nomenclatural discus- 

 sion under Scoliodon laticaudus). 

 Carcharias (Scoliodon) walbeehmi Bleeker, 1856, Nat. Tijdschr. Ned. Ind., vol. 



10, p. 253 (Bintang). 

 Carcharias (Scoliodon) crenidens Klunzinger, 1879, Sitzb. Akad. Wiss. Wien, vol. 



80, p. 426, pi. 8, fig. 3 (Queensland). 

 Scoliodon longmani Ogilby, 1912, Mem. Queensland Mus., vol. 1, p. 30 (Moreton 



Bay). 

 Scoliodon vagatus Garman, 1913, Mem. Mus. Comp. Zool., vol. 36 (text), p. 116 



(Zanzibar), 

 Carcharias eumeces Pietschmann, 1913, Jahrb. Nassauischen Ver. Naturk., vol. 



66, p. 172, p. 1 (Bibundi). 



Diagnosis.— Upper labial furrow well developed, 1.4 to 2.0 percent 

 of t.l. ; precaudal centra markedly elongate in posterior monospondy- 

 lous region (as in plate 2a) ; precaudal vertebrae less in number than 

 caudal vertebrae (equal in 1 out of 124 specimens) ; anterior margin 

 of pectoral fin usually equal to, or shorter than, total length of first 

 dorsal fin (79 out of 102 specimens); snout in front of nostrils 4.6-5.4 

 percent of t.l. in specimens less than 575 mm. t.l. (54 specimens; 

 4.0-4.5 percent in 8 specimens); 4.2-5.1 percent in specimens over 

 575 mm. t.l.; total teeth in outer row of upper jaw usually 25 (63 

 specimens out of 75); total teeth in outer row of lower jaw usually 

 24 (66 specimens out of 74); total enlarged hyomandibular pores 

 usually more than 16 (110 out of 118 specimens); first dorsal origin 

 usually slightly in advance of level of appressed pectoral inner corner 

 (ranging to just behind inner corner); origin of second dorsal fin 

 ranges from above posterior third of anal base to over anal axil; tip 

 of appressed pectoral fin usually reaches to below, or beyond level of, 

 the anterior third of the first dorsal base (infrequently only to the 

 anterior fifth). Males maturing only at sizes over 600 mm. 



Description (see also table 10). — Precaudal vertebrae 55-79 (table 

 9); caudal vertebrae 64-83; total vertebrae 121-162; upper teeth 

 11-1-11 to 13-1-13 (usually 12-1-12); lower teeth 11-11 to 13-13 

 (usually 12-12); cusps of some upper teeth in large specimens faintly 



