TliE T«ORN«ACK. lis 



I'he Vsornhach^. 



\ HE thoi-nback is the laft of this genus which we flialJ. 

 particulai-ife j and its figure is fo well known, that a fliort 

 defcription will fuffice. It is of a rhomboidal ihape, 

 broader, however, than long, and diilinguiflied from all 

 the other fpecies of the raj, by three rows of fpines upon 

 the back, and five upon the tail, all pointing towards its 

 end. The mouth is fmall, and fitted with granulated 

 teeth; between the nofe and the eyes are a few fpines ; o- 

 thers are fcattered without any order upon the peftorai 

 fins. 



The colour of the upper part of the body is that of 

 pale aflies, marked with Hreaks of black, and the (kin 

 rough, with fmall tubercles like fhagreen. The belly is 

 white, crofTed with a flrong femilunar cartilage f. Wil' 

 loughhy has given a long detail of the internal ftru£lure 

 of this fpecies ; by which it appears, that it has two di- 

 flin£l organs, of a curious conformation, one on each fide, 

 for generating and excluding its eggs : In thefe are depo- 

 fited innumerable ova of various fizes J; hence, the thorn- 

 back mull be very prolific. It begins to generate in the 

 month of June, and continues production till September ; 

 its young, as long they are incapable of breeding, are 

 called maids ; they are good eating at all times of the 

 year, but the old only begin to be in feafon in the month 

 of November. 



Vol. III. P The 



* Fail clavata. I,in. Syft, Idem Rondeletii ct Will. 

 I Britifli Zool. t Ichthyol. p. 76, 



