HARDWICKE'S SCIENCE-GOSSIP. 



173 



upon the young prawns and other "merchantable" 

 things which are diminishing in an alarming manner 

 with each succeeding year ; everybody is crying out 

 about the awl'ul price of oysters and prawns and all 



It has been suggested, rather than asserted, that 

 by means of this peculiar compound hollow fin the 

 Rock-Goby can attach itself to rocks in a vertical 

 position, on the vacuum principle. This particular 



Fig. 90. The Armed Bull-head, or Po^ge {Aspido/ihorus Euvopmus) 



other sea food, but nobody stops the wanton mis- 

 chief that makes the scarcity. 



Here is a Rock-Goby, Gobius niger, the largest and 

 rarest of the eight species of the Goby tribe which 

 have been described and classed as British. A speci- 

 men which we captured on the Horse shoal lived and 

 thrived in the aquarium for seven months. Al- 

 though a veritable niger, he was not by any means 

 black, or even dark, nor did he turn black when 

 irritated or excited. Observation has convinced us 

 that many aquatic creatures, especially when young, 

 vary so immensely in their colour and general out- 

 ward appearance in different localities, that they 

 can only be distinguished and identified with 

 certainty by a careful examination. Our prisoner 

 was of a light yellowish-brown, and mottled about 

 the back with a darker brown, with a few purplish 

 spots on the dorsals and a row of greenish-brown 

 marks along the median line : no doubt his coat was 

 adapted to the colour of the gravelly bed on which 

 he dwelt ; perhaps if his lot had been cast upon a 

 blue-clay bottom, he would have assumed a more 

 Ethiopian hue. He was very wild and shy, hiding 

 for weeks together behind stones and weeds; he 

 would dash out savagely at a morsel of meat, and 

 dart back again to his lair like a flash of lightning. 

 These movements were executed so rapidly that the 

 eye scarcely received any distinct impression of the 

 animal itself, — a streak of light and a disastrous up- 

 setting of miniature groves and grottos, and a whirl- 

 ing about of the bits of rubbish stirred up from the 

 bottom, were the indications of one of his hungry 

 raids. The ventral fins are arranged in a very re- 

 markable manner, being united together by their 

 anterior and posterior edges ; the pair thus form- 

 ing a kind of oblique infundibulum, the so - called 

 " sucking-fin," which is not very easy to describe, 

 but may perhaps be understood on referring to 

 fig. 91, where it is well shown. We took the idea of 

 this figure from Yarrell, but it has been drawn to 

 life size, from one of our own specimens. 



specimen never made any such use of it ; he invari- 

 ably grovelled on the bottom ventre a terre, as flat 

 as a flounder. A small and very tame successor who 

 is at present our guest, swims about freely. The 

 spiny sticklebacks, though nearly twice his size, 



Fig-. 91. The Rock-Goby {Gobius niger). Ventral aspect. 



have a great respect for him ; he has no hesitation 

 in charging straight into the middle of half a dozen 

 of them and taking away apiece of meat which they 

 are quarrelling about. After watching him daily for 

 weeks and weeks, we began to feel sure that the 

 idea put forward in a doubting sort of way by 

 Montagu and others about the Goby's habit of ad- 

 hering to plane surfaces by the " sucking-fin " was 

 a myth ; when behold, at last, we found him most 

 unmistakably affixed by the said contrivance to the 

 smooth side of the polished plate-glass of his house- 

 of-detention, where we had ample opportunity of 

 scrutinizing his united ventrals with a pocket lens. 

 It required some little force to remove him from his 

 hold with a netting-needle. We have no longer any 

 doubt on the point ourselves ; and it has been satis- 

 factory to find, on rummaging amongst the heaps 

 of valuable odds and ends in the back numbers 

 of Science-Gossip, that another correspondent 

 (page 42, Feb. 1865) is equally certain. We expect 

 shortly a deposit of eggs by the prisoner's wife, and 



