388 Survey of Fishing-Grounds, West Coast of Ireland, 1890—1891. 



length of the disk being, respectively, 36 and 31^ inches. The snout was 

 12 inches long, or exactly one third of the width of the disk. The weight was 

 32 lbs. The colour different from that of the last specimen, only in the presence 

 of some irregular roundish lighter blotches on the upper surface, a difference of 

 small importance under any circumstances, and of none at all when, as in the 

 present instance, the variegated example came from only 38 fathoms, and the 

 uniform example from some depth between 500 and 375 fathoms. There is no 

 important difference in proportions between the two, but the spinulation differs in 

 the entire absence of median caudal spines from the larger specimen. The lateral 

 row is also wanting behind the level of the centre of the first dorsal. 



Seeing that in the 50-inch specimen the median spines had almost disappeared, 

 it is not surprising to find no trace of them in a fish 3 inches longer; yet the 

 distinction between R. oxyrhynchus, and R. vomer seems to be based on the 

 respective presence and absence of these spines. The two species were 

 amalgamated by Day, but Lilljeborg, a more recent autlior, admits R. oxyrhynchus 

 to the synonomy of R. vomer, only with the prefix of a note of interrogation. 

 We venture to think that the observations recorded above most fully confirm the 

 correctness of Day's opinion, and since, as we have noted in our introductory 

 statement on the Raiidae, the adult male is almost invariably less spinous 

 than the female, we think it likely that males may lose the median spines earlier 

 than is the case with females. Unfortunately no notes were made on the 

 spinulation of the males, nor were any preserved, but a large male was examined 

 and measured by one of us on the same date as the female of 53 inches, and, in 

 the absence of any note to the contrary, we are, perhaps, justified in inferring 

 that it did not differ from the female in a character so important as that of the 

 median spines. The total length of this example was 48 inches, the length and 

 width of the disk 29 and 33|- inches, and the length of the snout 10^ inches. It 

 weighed 25 lbs. 



The largest example taken during the survey was 63 inches long, but no 

 record was made of the width of the disk or other measurements. 



A rather interesting condition of spinulation is exhibited by a young female, 

 measuring 22^ inches across the disk, which, though derived from the North Sea, 

 is useful for comparison with the Irish specimens, since no others from Irish 

 waters are available. The median caudal row is fairly complete, eight spines 

 remaining, while scars mark the sites of two others. The spines, however, are 

 much worn, nothing but the base and a slight apical prominence remaining. The 

 lateral rows are only represented by one spine on one side, and two on the other, 

 all posterior to the commencement of the first dorsal fin. They are evidently of 

 recent growth, since they are quite perfect and sharp, and, no doubt, represent 

 the first appearance of the more or less continuous row, which manifests itself in 



