250 PLAQIOSTOMI. 



" Length of recent ovum of Scyllium Catulas f 4 inches 6 lines ; breadth 1 

 inch 9 lines ; depth 3 — 1 lines ; surface smooth or plaited transversely ; sides 

 very strong and closely plaited throughout ; tendrils very strong. Colour a 

 uniform brown, but differing in shade in different ova. 



" Belfast, May, 1844." 



The Blaok-moutiied Dog-fish, Pristiuriis melanostomus, Bonap., 

 Scyllium melanostomian, Bon., 



Has been obtained on the northern coast. 



We are indebted to the Ord. Sui-vey' for this addition to our Fauna, 

 two individuals having been obtained by the collectors at Portrush, near 

 the Giant's Causeway. Captain Portlock, in contributing a notice of this 

 shark, observed that " in the work of Muller and Henle, the genus Pris- 

 tiuriis, Bonap., is described as having a row of small prickles on the tail- 

 fin, and Sci/llitiin Artedi is figured and described by Risso as having but 

 a single row. — In Yarrell's description of Scijll. melanostomnm two rows 

 are mentioned, and in our specimens they certainly exist, — ought not, 

 therefore, the single row to be dropped as a generic character, and 

 Risso's termination of his specific charactei's used, viz. ' pinna dorsi ex- 

 tremitate [supra] spinosa ? ' may not the one and two-rowed individuals 

 be of distinct species, and the black mouth be common to both ? " Mi*. 

 Yarrell, in his second ed. of Br. Fishes, vol. ii. p. 497, says, " it has also 

 been taken in the North of Ireland by Captain Portlock, to whom I am 

 indebted for sketches, from which the diflerent subjects forming the 

 vignette at the end were taken." 



The Fox-shaek, or Thresher, Carcharias Vulpes, Cuv., 



Can be announced only on circumstantial evidence as frequenting the 

 Irish coast. 



M'Skimmin, in his History of Carrickfergus (3rd edit. p. 358), notices 

 the 



" Squalus Vulpes, Sea-Fox Thresher ; sometimes seen off the Copeland Islands, 

 and heard after night making a noise with its tail against the water." 



Templeton includes the species in his Catalogue, remarking merely 

 that it is " rare on the coast, but occasionally seen about the Copeland 

 Islands." 



Major Walker, of The Lodge, County Wexford, noticed this species in 

 a letter written to me in July, 1846, from the statement of fishermen who 

 had seen a large fish beating a grampus or small whale in the Sound, be- 

 tween the two Saltee Islands, and who reported that every blow " sounded 

 like the distant report of a cannon." This description will apply only to 

 the species under consideration, which owes its name of Thresher to the 

 propensity here mentioned. 



" Mr. Couch says it is not uncommon for a thresher to approach a herd 

 of dolphins [Delphini) that may be sporting in unsuspicious security, and, 

 by one splash of its tail on the water, put them all to flight like so many 

 hares before a hound." — yarrell's Brit. Fish., vol. ii. p. 523. 



The Blue Shark, Carcharias (/laiicus, Cuv., 



Is taken on the coast, chiefly southwards. 



Dr. Ball informs me that this species is occasionally captured at the 

 Nymph Bank, and also at Youghal. I examined the jaw of one from the 

 former locality, in that gentleman's collection : the fish to which it be- 



