340 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 
I have had an opportunity of watching them in the breeding 
season they are equally domestic, as they are undoubtedly 
intelligent. The fact that one is viviparous points to closer 
relations between the sexes in this genus, and supplies fresh 
reasons for the gay and attractive ornamentation of some species, 
such as would hardly have been anticipated. Perhaps the gayest 
of the whole shore group, however, is that comprising the various 
Sucker-fishes (Gobiesocide), and it may be worth while examining 
them more partieularly in case they may throw some light on the 
whole question of coloration. 
In the first place, then, Sucker-fishes differ from gregarious and 
most deep-water fishes in a distinct difference in appearance 
between the male and female. This in itself is a great advance 
in differentiation, and allows for the development of the sexual 
affections and sentiments in a way that may be said to “ civilise” 
the possessors. Along with this, there is a great variation in 
individual appearance, such as results from the domestication of 
terrestrial animals, but is not commonly found amongst any 
wild animals whatever. This differentiation has made the 
elucidation of species exceedingly difficult, so much so that no 
two works agree in these, and I cannot quite find myself in 
agreement with any of our standard works. Here, then, we have 
a charming group of fishes, trusting mainly to its inshore habitat 
and concealment under stones for escape, and displaying its charms 
to the best advantage, and the colouring of which, in all reason- 
able probability, is the result of sexual stimulation. One of these 
taken in deeper: water, the dainty little Two-spot Sucker 
(Lepadogaster bimaculatus (Donov.) ), that specially haunts scallop- 
beds, and chooses an empty and partially open scallop-shell for its 
ordinary nursery, presents fewer variations than its more tangle- 
zone congener, the Cornish Sucker (Lepadogaster Decandolit, 
Risso). Yet we have taken specimens decidedly different from 
the ordinary type, and the most brilliant and charming little 
creatures we have ever seen emerge from the water. They are 
extremely domestic, and watch over their ova with assiduity. 
The same may be said of LZ. Decandolii, Risso, the male of which 
displays unwonted brilliance in the breeding season, and gives 
great prominence to the row of spots along the dorsal fin. It is 
probable that these, as in the similar case of the Gunnel Fish, are 
