Holt and Caldeewood — Report on the Rarer Fishes. 435 



median cavity of the occiput is relatively narrower than in full-grown fish. 

 Specimens of an inch exhibit only the cavities of the snout. The obliquity 

 of the jaws is a feature which appears also to increase with the growth of the 

 individual. 



Examples of less than 3 inches show very little coloration, except the silvery 

 pigment of the sides of the head and abdomen ; but the top of the head and the 

 dorsum are speckled with dark chromatophores. These, in specimens of about an 

 inch, show a tendency towards an arrangement into five short transverse bars, 

 of which some traces remain in specimens of 3 inches. Larger examples show 

 the general dull silvery coloration so well depicted in Gruichenot's figure of 

 the type. 



From the examination of our specimens it appears that vomerine teeth are 

 always present in young examples, though are few in number and loosely 

 attached. They are altogether wanting in many of our larger specimens. The 

 species is thus common along the west coast of Ireland at suitable depths, and 

 is evidently there gregarious at all stages of its existence, as also, according 

 to Vaillant, in the regions explored by the "Talisman" and " Travailleur." 

 The importance to be attached to the occurrence of only young examples, on the 

 Irish coast, above the 100-fathoms line may perhaps be overrated, since the net in 

 which they were caught was a small shrimp trawl,* which might well be evaded 

 by lai'ger examples. The absence of small examples from greater depths may 

 very probably mean nothing more than that the meshes of the larger trawls were 

 not fine enough to retain them. At the same time it must be noted that fishes at 

 least as active as full-grown G. argenteiis were not infrequently taken in the 

 small net, while it is probable that, if any quantity of small examples had passed 

 through the meshes of the larger trawls, some would have been found adhering 

 to the spines of the Spatangi. It is also possible that the comjDaratively late 

 development of the mucous cavities of the head may be in relation to some 

 developmental change in the vertical habitat of the species. As we have seen 

 above, it is one which lives, as it were, on the borders of the abyss, never rising 

 into quite shallow water, and never, apparently, penetrating into very great 

 depths. 



Genus Mora, Risso. 



Body moderately elongate, covered with scales of moderate size. A separate 

 caudal ; two dorsal and two anal fins ; ventrals composed of six rays. Teeth 

 small, curdiform, of equal size, in the upper jaw in a band ; teeth on the vomer 

 and sometimes on the palatine bones. Branchiostegals seven. (Giinther.) 



* Sts. 114 and 115. 



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