IN THE SOUTH-WESTERN DISTRICT. 109 



I do not propose to discuss, except incidentally, the developmental 

 habitat of the species dealt with, these notes being only designed to 

 assist in the determination of the young stages. A word is necessary 

 with regard to the references given under various species to M'Intosh 

 and ]\Iasterman's Life Histories of British Fishes. This book con- 

 veniently summarises the numerous and important observations of 

 Professor M'Intosh, which appeared originally in a great number of 

 papers in the Scottish Fishery Board reports and elsewhere ; it may also 

 be taken as setting forth his most recent opinion on matters of doubt. 

 I have therefore referred to it in preference to the original papers. 



Trigla lineata. Gm. Linn. Polperro bull-dog, Parrot gurnard. 



The Polperro bull-dog, as it is generally called at Plymouth, is one of 

 the commonest gurnards of the district. It frequents the rather deep 

 water from a few miles beyond the Breakwater outwards, though I 

 have known it to be taken on one occasion in Cawsand Bay. The 

 young stages have not been found in the estuary or inshore waters, and 

 I do not think that we have ever taken the ova in tow-nets. It 

 therefore spawns in all probability on off-shore grounds, and apparently 

 towards the end of the summer. A female taken on the 31st July, 

 1897, proved to be nearly ready to spawn, since the ovaries contained a 

 few translucent eggs. Artificial fertilisation was attempted. After the 

 lapse of an hour and thirty-five minutes three eggs were still floating. 

 One had reached the two-cell stage, the others may or may not have 

 been impregnated. 



These eggs measure from 1"29 to 1"33 mm. in diameter. The single 

 dark, but not conspicuously coloured oil-globule measures, in all threa 

 cases, "24 mm. The zona is strongly ridged, but this is probably an 

 ovarian character. The ova were all dead on the following day. 



Trigia hirundo. Bloch. Tub (Plymouth), Latchett (North Sea). 



■? Marion, A. F., Annates Mus. Mars., iv., 1891, I., p. 120, PI. II., Fig. 19. 

 Early larva. 



Holt, E. W. L., Ann. Mus. Mars., v., Fasc. II., 1898. Tow-net egg, larva, young 

 l)elagic form. 



The Tub is the most economically important gurnard of the 

 Plymouth district; but, although young specimens are common 

 throughout the year, the adults appear to leave the grounds near 

 Plymouth before the breeding season. I have never had an 

 opportunity of submitting ova, obtained directly from the parent, to 

 exact observation. Speaking rather generally, I can say that spawning 

 takes place in the summer or early autumn. 



II 2 



