264 THE PLAGIOSTOMIA. 



width, and more than half of that from the mouth. Mouth wide, about one 

 sixth of the preoral length, slightly arched forward; la})ial folds rudimentary. 

 Teeth very small, in pavement, seventy-eight rows in the upper series, seventy- 

 six in the lower. Gill openings small, hindmost smallest, outer edges of valves 

 in sigmoid curves. Eye medium, behind a vertical from the nostril, with a nar- 

 row subtriangular velum reaching downward across the pupil; orbit elongate. 

 Spiracles half as large as the eye, obhquely placed about one diameter behind the 

 orbit. Pectorals more than twice as long as wide, outer angle obtuse, hinder 

 acute, free portion less than width of fin. Origin of first dorsal half way between 

 that of the ventrals and the middle of their bases; second dorsal smaller; hind 

 angles of fins produced, posterior margins concave. A low keel at each side of 

 the tail; caudal fin rather small, subcaudal not lobed, obliquely truncate. The 

 scales are very small; the earliest of them bear some resemblances to those of 

 the very young of species of Rhina but the later growths show various modifica- 

 tions. The most common shape of scale perhaps is that with a broad base, a 

 stout peduncle and a smooth depressed crown sharp angled posteriorly; another 

 common form is that seen in the pavement squamation at the end of the rostrum 

 and on its lower surface, a rounded smooth convex crown sessile on the base. 



Olivaceous brown, yellowish to greenish, darker on the crown, fins lighter, 

 ventral surfaces white. 



Type from Queensland, Australia. 



Pkistis pristis. 



Pristis sive serra Clusius, 1605, Exoticorum, p. 136, figs. 



Squalus pristis Linne, 1758, Syst., 1, p. 235; 1766, Syst., 1, p. 401; Walbaum, 1792, Art. Gen. 



Pise, p. 504. 

 Pristis pristis Klein, 1779, Neuer schaupl., 7, p. 404. 

 Pristis antiquorum Latham, 1794, Trans. Linn. soc. London, 2, p. 277, pi. 26, f. 1; Muller & Henle, 



1841, Plagios., p. 105, pi. 60; Dumeril, 1865, Elasm., p. 473; Gunth., 1870, Cat. fishes Brit.mus., 



8, p. 438. 

 Pristis serra Schneider, 1801, Bloch Ichth., pi. 70. 

 Pristis canaliculata Schneider, 1801, Bloch Ichth., p. 351. 

 Prislibatis antiquorum Blainv., 1830, Poiss. Fr., p. 49. 



It is from Clusius that the species to which Linne gave the name Squalus 

 pristis is identified. As figured by Clusius there are fifteen to sixteen teeth on 

 each edge of the rostrum, the origin uf the first dorsal is above that of the ventrals, 

 the second dorsal is about as large as the first and does not reach the caudal, 

 and there is no subcaudal lobe. Later authors give sixteen to twenty pairs of 

 rostral teeth, trenchant on the forward edge. Rostrum broad, tapering. 



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