new Fishes from the South-west Coast of Ireland, 89 



Boulengei's suggestion (1903) tliat Cyttosoma is merely the 

 adult form of Oreosoma, C. & V., as higlilj probable, we 

 prefer not to apply the latter name to the genus now under 

 consideration until further material is available. 



For present purposes the genus may be defined as follows : — 



Cyttosoma (Gilch.). 



? Oreosoma, C. & V. 



Cyttosoma, Gilch. (1904 & l^QQ),-\-Neocyttus, Gilch. (1906). 



Form compressed and elevated, more or less rhomboidal ; 

 body and parts of head covered with moderate or small 

 ctenoid scales. Rows of bony scutes or tubercles sometimes * 

 present on belly and sides. No bony scutes or tubercles 

 along bases of dorsal and anal fins. Dorsal and anal fins 

 similar, their spinous and articulated rays continuous but 

 separated by notches. Dorsal spines VI-VII, anal III-IV. 

 Upper jaw protrusible. Small teeth in the jaws and usually 

 on vomer. 



Oreosoma atlanticum , C. & V., is known from two young 

 specimens only (the largest G8 mm. long) in which the bony 

 tubercles on the sides of the body are relatively enor- 

 mous ; there is nothing to definitely connect these with any 

 known adult form, but they may, as suggested by Boulenger 

 (1903), prove to be the young of some fish closely allied to 

 C. verrncosum. 



Of Pseudocyttus maculatus, Gilch. (190G), we have seen no 

 specimen, and the figure referred to in the original description 

 is as yet unpublished. The species is imperfectly characterized, 

 but is stated to have two anal si)ines only and cycloid scales, 

 and therefore does not not fall within the definition of 

 Cyttosoma above suggested. 



The characters which may prove to be valid for the 

 distinction of species of Cyttosoma at all stages are somewhat 

 uncertain. No reliance can be placed on the lines of bony 

 tubercles which occur in the young of some and, perhaps, of 

 all species, since, while in C. verrncosum they persist in large 

 examples, they disappear at a comparatively early stage in 

 C. hoops and are not present in any of the hitherto observed 

 stages of the other species. The scales probably maintain 

 tluir number, but it is not improbable that they become 

 smootlier with age and their asperities are rather easily 

 rubbed off, as, for instance, in the type of C. helga^, of wliicli 



* Probably always in young, but some species are known only from 

 speciuieus of a size at which the scutes have ahcadv beiii lost in others. 



