430 



Fam. 1. PRISTIDvE. 



The snout is produced into an exceedingly long, 

 flat lamina, armed with a series of strong teeth along 

 each edge (saw) *. 



1. PRISTIS. 



Pristis, Lntham, Trans. Linn. Soc. 1794, ii. p. 276. 



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 the 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., Klei7i, Pise. Miss. iii. p. 12, tab. 3. figs. 1 & 2. 



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



fig. 4 (rostrum). 

 Pristis perotteti, Miill. Sf Heiile, p. 108 ; Diimeril, Elasmobr. p. 474. 



antiquorum, Cosfn, Fauna Reyn. Nap. Peso. pis. 8 & 9. 



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



zysron, Bleek. 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 following. Root of the pectoral in advance of 



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

 hollow subcjlindrical 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 

 in nearly all Rays, though shorter and much less developed. It is very diflicult 

 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 unexplained 

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

 of " Myriosteoii " (Proc. Zool. Soc. 18G4, April 12), and r-mamed a puizle to 

 zoologists until Prof. KoUiker, 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 the nature of this specimen had been thus 

 determined we di.«coverod th;>t it is one of the laleral tubes of the saw of Prisfis. 



