43'> ■ PEisTiD-i:. 



Fam. 1. PRISTID^. 



The snout is produced into an exceedingly long, 

 flat lamina, armed with a series of strong teeth along 

 each edge (saw) *. 



1. PRISTIS. 



Pristis, Latham, Trans. Linn. Soc. 1794, ii. p. 27G. 



Body depressed and elongate. Pectoral fins with the front margin 

 quite free, not extending to the head. Gill-openings inferior, in- 

 wards of the base of the pectoral fin, of moderate width. Spiracles 

 wide, behind the eye. No nictitating membrane. Nostrils inferior; 

 no tentacles. Teeth minute, obtuse. Dorsal fins without spine, 

 the first opposite or close to the base of the ventrals. 



Seas of tic tropical and subtropical regions. 



The size of the teeth cannot be used as a specific character, as it 

 is subject to much individual variation. 



1. Pristis perrotteti. 



Galeus, sp., Klein, Pise. Miss. iii. p. 12, tab. .3. figs. 1 & 2. 



? Pristis microdon, Latham, Trans. Linn. Soc. 1794, ii. p. 280, tab. 20. 



fig. 4 (rostrum). 

 Pristis perotteti, Miill. i.^'- Hcnle, p. 108 ; Dumeril, Elasmohr. p. 474. 



antiquorum, Costa, Fauna Regn. Nap. Peso. pis. 8 & 9. 



microdon, Bleek. Verh. Bat. Gen. xxiv. Plagiost. p. 54. 



zysron, Pleeh. Nat. Ti/ds. Ned. Ind. iii. p. 441 (not Verh. Bat. 



Gen.). 



Dorsal fin nearly entirely in advance of the ventrals. Eighteen 



or twenty pairs of rostral teeth, not trenchant behind, and distant 



from one another, the base of each tooth being about one-third of 



its distance from the foUowmg. Eoot of the pectoral in advance of 



* The endoskpleton of the saw consists of three, sometimes five, rarely four, 

 hollow subcylindrioal tubes, tapering towards the end, incrusted with osseous 

 deposit, which has a granular appearance, and is perforated by small foramina. 

 These tubes are the rostral processes of the cranial cartilage as they are observed 

 ill nearly all Rays, though shorter and much less developed. It is very difficult 

 to remove them "out of the saw in their integrity. However, one of these bodies, 

 which is in the British Museum, became detached in an at present unexjjlained 

 manner, and is perfectly intact. It was described by Dr. Gray under the name 

 of " Myriosteon " (Proc. Zool. Soc. 1864, April 12), and rrmnined a puzzle to 

 zoologists until Prof. Kcillikpr, during a recent visit to London, examined it 

 microscopically, and arrived at the conclusion that it must be " part of the endo- 

 skeleton of a Plagiostome." After tlie nature of this specimen had been thus 

 determined we di.^covercd that it is one of the lateral tubes of the saw of Pristis. 



