104 EEPOET— 1889. 



also as observed by Professor Parker in the Red Cod, Lotella baccJms.^ But 

 after the most careful dissection the bladder still appeared to end blindly, 

 and without coming in contact with any modified bones which might 

 serve as ossicles of the auditory apparatus. 



I may here mention also that there is no communication between the 

 bladder and oesophagus. 



The histology of the bladdei', although interesting in many respects, 

 cannot be entered into here, but must form the subject of a future paper. 



The flying powers of Dactylopterus are by some, I find, called into 

 question. Making inquiries about such habits of the fish as are known, 

 I am informed by Signer Lo Bianco, of the Naples station, that it is met 

 with in the Bay at a depth of from 20-60 metres, say 10-30 fathoms, but 

 is never seen on the surface. 



In the literature on the subject there are two or three very old notes, 

 merely saying that the fish flies or has been seen flying. Then Miibius, 

 who has written largely on the flying powers of Exor.oiius, describes its 

 flight when discussing whether flying fish move their wings or not. He 

 compares the flight to that seen in many grasshoppers, ' which raise 

 themselves from the ground with a spring, and, eking out their momen- 

 tum as much as they can by buzzing their wings, fall to the ground after 

 a short flight.' 



Moseley - refers twice to their flight, the second time when he was 

 collecting amongst the weed of the Sarago-sa Sea. This instance seems 

 to me to be conclusive, I therefore quote it. 'I watched these little flying 

 fish fly along before the boat at a height of about a foot above the water 

 for distances of 15 or 20 yards, and I chased them and caught one or two 

 with a hand-net amongst the weed.' 



Prom a study of the young Dadi/loptenis, i.e. the fish formerly known 

 as Gephalacanthus, it is evident that only the adults can have the power of 

 ' flight.' The smallest specimen I had an opportunity of examining was 

 1^ inches. The pectorals, when placed along the side, reached to a level 

 of the second dorsal fin-ray — a fin so short as to be quite insignificant 

 as a flying organ. In the full-grown fish the pectorals, when placed in 

 the same position, reach quite to the base of the caudal fin, and when 

 spread out in an extended position form huge, beautifully-coloured wings. 

 This condition is approached to some extent in Trigla lyra, a gurnard not 

 uncommon in British waters. Although very closely allied to the Triglidse, 

 Giinther does not include Dactylopterus in that genus, but places it in the 

 Cataphractidae, a small group repi'esented on our shores only by the 

 Pogge, Agonus caiaphractus, a fish living amongst the weeds at the 

 bottom. 



Without doubting the flying powers of Dadylnpterus, I am inclined to 

 think that it is also in the main a non-pelagic fish. The peculiar struc- 

 ture and position of the swimming-bladder, amongst other things, point, 

 I think, in this direction. 



The bladder of the gurnard is well known — thin-walled and non- 

 muscular — situated in the dorsum of the aldominal cavity. When a 

 gurnard is brought suddenly to the surface it almost invariably turns 

 belly upwards and swims or floats in this position. This is caused, I 

 think, by the sudden expansion of the contained gas, consequent upon 



' Parker, T. Jeffrej- : Trans. N. Z. Instit. vol. xv., ] 882, p. 234. 

 ^ Moseley: A'otcs by a Naturalist im the 'ChaUnitier,' p. SG2. 



