November, 1922. 



The Canadian Field-Naturalist 



157 



the ommission of the unique freshwater-sponge 

 collected by Prof. Macoun in the lake-pond 

 situated in the centre of Sable Island, N.S., and 

 described by Dr. A. H. MacKay, of Halifax, as 

 Heteromeyenia macouni n. sp., in Trans. N.S. 

 Inst. Scien., Vol. X, 1899-1900. 



Apart from the fact that it commemorates 

 Prof. Macoun's important stay upon the island 

 during the summer of 1899, and increases the list 

 of animals named after him from five to six, I 

 think that the record is also of importance as 

 showing his interest in freshwater life as well as 

 in that upon land and in the sea. — Frits Johan- 



gEN. 



Acuteness of Vision in Pagurus arcadianus. — 

 The compound eye of Arthropods is extremely 

 well adapted to perceive movement but not so 

 well adapted for accurate perception of form. It 

 has been shown experimentally that ants of the 

 genus Formica can see large stationary objects at 

 a distance of 10 centimeters, but cannot see small 

 objects, that is, objects of their own size, further 

 than 5 millimeters. Dragonflies, which, as far 

 as known, have the most acute vision of all 

 Arthropods, appear to be able to perceive the 

 form of objects at 2 meters. It is not always 

 easy, in fact it is often extremely difficult, to say 

 what sense is involved in bringing about a certain 

 action in an insect or a crustacean. Many 

 reactions of these animals which are casually put 

 down as being due to sight are found on experi- 

 ment to be due to some other sense, and any 

 exact data on this matter are of interest from the 

 standpoint of animal psychology. 



At the Atlantic Biological Station in August, 



1921, we took six Hermit Crabs, Pagurus arca- 

 dianus, out of the shells of the Whelk, Buccinum 

 undalum, which they had inhabited, and placed 

 the crabs in one of the large shallow tanks of 

 running sea water in the laboratory. We then 

 placed clean, sun-dried Whelk shells at various 

 distances from the Hermits. Up to a distance of 

 80 centimeters the crabs perceived the shells at 

 once, made straight for them, "measured them 

 up", outside and inside, with their chelae, and, if 

 they found them suitable, promptly inserted their 

 bodies into the shells. In this case, there is no 

 doubt that vision was the sense involved, since 

 the clean shells could not give off any substance 

 which could be perceived by the chemotactic 

 senses. — A. Brooker Klugh. 



Cassiope tetragona in Western Alberta. — 

 While collecting in the Rocky Mountains of 

 Western Alberta in September, 1922, I was for- 

 tunate in discovering a plant whose occurrence 

 at this point may prove interesting to many 

 botanists. I refer to the white or moss heather 

 (Cassiope tetragona). The locality was Rocky 

 Pass just south of Mountian Park, with an altitude 

 of about 7,000 feet. The specimen collected was 

 in a mossy spruce woods near timber-line. It is 

 evidently a far northern plant, for Dr. M. O. 

 Malte, Chief Botanist of the National Herbarium, 

 who very kindly identified this and all other 

 botanical specimens for me. has this to say of it: 

 "Concerning No. 673, I am glad to state that you 

 have brought the southern limit of this northern 

 plant a long way south. We have Cassiope 

 tetragona in our herbarium from numerous places 

 in the far north, the most southern locality, how- 

 ever, being from the Yukon district." — J. Dewey 



SOPER. 



BOOK REVIEW 



The Conservation of the Wild Life of Cana- 

 da.— (Cowciwded from Vol. XXXVI, No. 7, 

 p. HO)- 



While game laws with longer close seasons and 

 more restricted bag limits have done something to 

 prevent the rapid if not appalling diminution of 

 all kinds of game from the lordly moose to the 

 diminutive Plover and Sandpiper, the total result 

 in comparison with the annually increasing num- 

 ber of gunners and the improvement of weapons 

 of destruction is not encouraging. Of recent years 

 the sentiment seems to be growing among con- 

 servationists that the only hope of preserving a 

 remnant of many species is by establishing here 

 and there a nucleus in the shape of a pa'-k or 



sanctuary where destruction shall be absolutely 

 prohibited. Recognizing the legitimate needs of 

 sportsmen, these oases of protection, which may 

 also serve as forest reserves or recreation parks, 

 may preserve species which would otherwise 

 become absolutely extinct, and the overflow from 

 the boundaries afford a perennial and certain 

 supply to surrounding territory. The United 

 States have done much along such lines, but 

 Canada, a newer country with more unoccupied 

 land, has as Dr. Hornaday says, "set out to get 

 for herself a-plenty of national parks and game 

 preserves while the getting was good. No pro- 

 vince seemed disposed to be left behind in this 

 conservation enterprise. As a final result, these 

 red-spotted maps tell a great story of enlighten- 



