1. riusTis. 437 



the first gill-opening ; its outer angle is a right one. The second 

 dorsal not much smaller than the first. A small lower caudal lobe. 



Tropical seas. 

 «. Stuflfed, 4 feet long. Atlantic. From Sir A. Smith's Collection. 

 h. Stuffed, 4 feet long. West Indies. Purchased of Mr. Scrivener. 

 c, d. Three feet long. Chiapam. Prom Mr. Salvin's Collection. 



e. Skin in spirits. Bandjerraassing. Described as P. zysron by Dr. 



Bleekcr. 



f. Stuffed, 34 inches long. From the Collection of Dr. van Lidth 



de Jeude. 



g. Young. From the Collection of Dr. van Lidth de Jeude. 



h-i. Saws of half-grown specimens. Zambezi. Presented by Dr. 



Kirk. 

 k-l. Saws of half-grown specimens. From the Collection of Dr. van 



Lidth de Jeude. 



An examination of our examples must lead to the conviction that 

 the difference in the size of the rostral teeth cannot be used as a 

 specific character. Specimens c and cl are of nearly the same size, 

 were obtained at the same time and at the same locality, and agree 

 with each other in every respect except in the size of the rostral 

 teeth, which in the one example are two lines long and four in the 

 other. Younger examples, like specimen /, have still smaller teeth. 

 Such small-toothed examples have been called microdots by recent 

 authors ; but it is doubtful whether they are Latham's Pr. microdon, 

 as this appeared to have a much longer saw, viz. more than one- 

 third of the total length, whilst in our examples it is considerably 

 less than one-third. Latham states also distinctly that the -second 

 dorsal of his example was smaller than the first. 



2. Pristis pectinatus. 



Pristis pectinatus, Latham, Trans. Limi. Sec. 1794, ii. p. 278, pi. 26. 

 fig. 2 (rostrum) ; Jil. ScJin. p. 351, pi. 70. fig. 1 ; liissv, Ichtli. Nice, 

 p. 22; and Enr. Mcrid. iii. p. 141 ; U/auiv. Faun. Fr. p. 5 J ; Miill. 

 ^ Henle, p. 109; Bhjth, Joxinu As. Soc. Bnu/. 1800, xxix. p. 30 

 Ouen, Oduntorjr. pi. 8. fig. 1 ; Dumerd, Elasmobr. p. 475, 



Srpialus scie, Lacep. i. p. 280, pi. 8. 



I'listis megalodon, Dmncril, Elasmobr. p, 476, pi. 0. fig. 4, 



acutirostris, Dumeril, I. c. p. 479. 



occa, Dumeril, I. c. p. 479. 



leptodon, DinnerU, I. c. p. 480. 



brevirostris, DumcrU, I. c. p. 480. 



Origin of the dorsal fin opposite to that of the ventrals. From 24 

 to 32 pairs of rostral teeth, which are generally long and strong, but 

 sometimes rather short and feeble ; the anterior are placed close to 

 each other, the distance betM'cen them not being more than twic'^ 

 the base of a tooth. The three hindmost teeth are twice as remote 

 from one another as the anterior. The second dorsal fin is scarcely 

 smaller than the first. No lower caudal lobe. 



Tropical seas. 



