512 PISCES (CARTILAG.) PLAGIOSTOMI. [RAIA. 



maturity. (Colours.) Upper parts of a plain brown colour, without spots 

 or lines : under parts white, also without spots. MONT. 



This species, which I have not seen, is represented by authors as not 

 very uncommon in the British seas. Like the last it attains to a great 

 size. One obtained by Pennant in the Menai measured nearly seven 

 feet in length, and five feet two inches in breadth. Montagu states that 

 specimens have been taken of which the computed weight was above five 

 hundred pounds. As, however, in the case of R. Satis, the name of 

 Oxyrhinchus has been applied at different times to two or more perfectly 

 distinct species, and it is impossible to state whether we have not in our 

 seas more than one to which that name has been given. For this reason 

 I have not annexed any references except to Pennant and Montagu, 

 whose descriptions alone (of all our English authors) appear original, and 

 can with any certainty be referred to the same species. Whether the 

 present one be synonymous with the Oxyrhinchus of Willughby*, I 

 consider very doubtful. The R. Oxyrhinchus of Bloch t, as well as that 

 of Blainville $, appear quite distinct. 



201. R. marginata, Lacep. (Bordered Ray.) Snout 

 sharp, slender, moderately elongated, the lateral margins 

 nearly parallel at the tip : skin smooth : three rows of 

 spines on the tail : colour beneath white, with a broad dusky 

 border. 



R. marginata, Lacep. Hist. Nat. des Pom. torn. v. p. 663. pi. 20. 

 f. 2. Blainv. Faun. Franc, p. 19. pi. 3. f. 2. Flem. Brit. An. 

 p. 172. 



DIMENS. The following are those of an English specimen. Total 

 length fifteen inches six lines: length of the head (measured from 

 the end of the snout to the spiracles behind the eyes) three inches 

 six lines; of the tail (from the vent to its extremity) seven inches 

 nine lines : greatest breadth (across the pectorals) eleven inches three 

 lines. Obs. The total length of Blainville's specimen was two feet. 



DESCRIPT. (Form.) Rhomboidal ; the transverse diameter rather 

 more than one-third greater than the length from the end of the snout 

 to the vent: snout elongated, projecting considerably from between the 

 pectorals, terminating in a sharp point, with the lateral margins nearly 

 parallel for the last quarter of their length : mouth moderately wide ; 

 jaws transverse; teeth numerous, closely set, in several rows, roundish, 

 or somewhat quadrilateral, at the base, each terminating in a sharp point : 

 nostrils in a line with the corners of the mouth, and rather more than 

 half-way between them and the upper margins of the pectorals ; a chan- 

 nel from the nostrils to the mouth, covered by a membranous flap : eyes 

 and spiracles both large : skin perfectly smooth above ; also beneath, 

 excepting along the anterior margins of the pectorals and the surface 

 of the snout, which are set with very minute spines and denticles : one 

 large sharp spine above each eye, inclining backwards, and another 

 smaller one behind each eye: no spines on any part of the back, but 

 three rows on the tail, one occupying the middle ridge, the two others 

 the sides; the spines on these rows strong and sharp, and mostly in- 

 clining backwards : tail scarcely longer than the body, depressed, rather 



* Hist. Pise. p. 71. tab. C. 4. 1 IcMh. pi. 80. 



Faun. Franc, p. 18. pi. 3. f. 1. 



