igo6] Zoological Report 1905-6. 57 



sharks, mackerel, etc., do not possess a swim-bladder, hence it is 

 not essential tor flotation. Fresh-water suckers, cat-fishes, etc., 

 have a swim-bladder, and are not exceptionally buoyant. II it is a 

 barometer, why do so many species not possess it, while if it is of 

 use in some cases in connection with voice, it must be noted that 

 most fishes possessing - a swim-bladder are voiceless, and again as 

 an aid in hearing, it is no doubt of utility in rare cases, but such 

 is not its common purpose. The features of the organ in young 

 larval fishes indicate a glandular character and it may be a sur- 

 vival of a gland attached to the digestive system, whose utility 

 has gone. In most cases pure aerated blood supplies the swim- 

 bladder, and it cannot be respiratory excepting in rare instances, 

 and being dorsal it is difficult to see how it can be homologous, 

 as many authorities claim, with the ventrally placed lungs of 

 higher vertebrates. Professor Prince also stated that while 

 oxygen was often found in the swim-bladder, that organ frequently 

 appeared to be filled with nitrogen, an element associated in 

 many animals with the hibernating habit, or with change of food. 

 At the second meeting of the branch, held on the 22nd May, 

 1905, besides the chairman, Prof. Prince, there were present 

 Professor Macoun, and Messrs. Lemieux, Baldwin, Campbell, and 

 Halkett. Mr. Campbell showed some living specimens of 

 branchiate larvae, which appeared to be those of Amblystoma, and 

 Mr. Lemieux brought a single antler of the Virginian Deer, which 

 had been picked up beside a lake in the province of Quebec, soon 

 after it had been shed. It was a fine example, and of unusual 

 interest owing to the fact that shed antlers are very rarely found. 

 The members present discussed the remarkable phenomenon, the 

 annual shedding of deers' horns, the massive antlers of the moose 

 being specially mentioned as surprising structures to grow in a 

 single season, and then be ' cast away. Mr. Halkett shewed a 

 specimen of the dor-mouse {Evolomys rutilus), which he caught 

 with the hand, a year or two ago, at Madawaska, in the Nippiss- 

 ing district, and also a specimen of a bat (Vespertilio subulatus) 

 which was found alive in the Fisheries Museum, and which is one 

 of several specimens found there ; and a scheme was discussed, 

 led by Prof. Macoun, for securing specimens of small mammals in 

 the vicinity of Ottawa. Small traps were described, which if set 



