THE TROUT 67 



According to Thompson, the Lough Neagh 

 " Gillaroo " has the upper parts yellowish with large 

 brown spots, and towards the belly is golden, tinged 

 with pink, and with large scarlet spots on and 

 below the lateral line. It has a hard stomach or 

 gizzard, is partial to a rocky bottom, and may be 

 taken with a worm or a fly. It attains a weight of 

 1 2 Ibs., and the fishermen say that it is a very 

 inferior fish for the table. Thompson contrasts this 

 form with the Great Lake Trout, which grows much 

 larger and is described as silver-grey with black 

 spots, the males having a salmon tint below, and the 

 lower spots enclosed in orange rings ; this is taken 

 on night lines baited with Pollan or Perch, and is, 

 according to Thompson, the common Trout of 

 Lough Neagh. 



In a case like this one would like to know 

 whether there is an incipient species formation due 

 to physiological isolation. Whether " once a Gillaroo 

 always a Gillaroo " would hold good, or whether the 

 larger Gillaroos adopt the habits and assume the 

 livery of the ferox, thus taking a new lease of life. 

 Supposing the former to be the case, it would then 

 be a question whether the two forms keep apart 

 when breeding, and if so, whether the offspring follow 

 in the footsteps of their parents. 



Other localities for Gillaroo are the lakes of 

 Galway and Lough Melvin. Concerning the latter 

 Dr. Giinther tells me that a fishmonger once wrote 

 to inform him that he had received a number of 

 Gillaroo from Lough Melvin ; he went to look at 

 them and could feel the hard stomach by pressing 

 with his fingers; one fine specimen he purchased, 

 and afterwards cut it open in order to ascertain the 



