OF THE BRITISH ISLANDS. 47 



collecting in the Channel Islands, the writer has, in fact, on 

 turning the rocks over in search of specimens, dislodged 

 what at first sight, from the apparently large size of its 

 head, was taken for a Bullhead (Cottus), but which on closer 

 examination proved to be an example of the Rock Goby, 

 with its opercula and branchiostegal membranes abnor- 

 mally distended, with the evident intention of passing itself 

 off as one of those spiny-headed Cottidos, which are not to 

 be handled with impunity. A like imitation of a hurtful or 

 stronger form is adopted, as a means of protection, by 

 harmless and weaker species in many departments of the 

 Animal Kingdom. The coalescence into a single funnel- 

 shaped organ of the usually separated pair of ventral fins, 

 is a very distinctive feature of the Gobies, and prepares the 

 way for that further modification of this region, that obtains 

 among the true Sucking-fishes, Discoboli and Gobies ocidce. 

 This funnel-shaped fin expansion is, indeed, utilised by the 

 Gobies as an adherent organ or acetabulum, these fish, as 

 may be verified by watching them in an aquarium, being able 

 with the aid of such structure to adhere firmly to the 

 smooth surface of the glass front of their tank. Some of 

 the smaller Gobies are remarkable for their brilliant 

 colouration, one in particular, the Paganellus (Gobius 

 paganellus), No. 58, having its brown-mottled body 

 relieved by the dorsal fins, which are ornamented with 

 two broad, longitudinal bands of red and blue. This 

 fish grows to about half the length of the Black Goby, but 

 is relatively shorter and thicker. On the Jersey coast, at 

 very low spring tides — the vertical rise and fall averaging 

 at such times between forty and fifty feet — the writer has 

 obtained a species of Goby that is yet more brilliantly 

 coloured, and which he has not yet been able to identify 

 precisely with either any British or Continental form 



