Things to be observed in Canada. 3 



" The writer would also be particularly obliged by specimens of 

 spongi Use, or fresh-water sponges, as he is engaged on a mono- 

 graph of that tribe. They are found in rivers, lakes or tanks, and 

 pools, attached to dead wood, rocks or stones, and are occasion- 

 ally found surrounding the branches of trees, dipping into the 

 water during periodical floods; and if they contain their granular, 

 seed-like bodies, they are the more valuable. Dry them just as 

 they come from the water. If it be deemed necessary to preserve 

 parts or the whole of delicate specimens of either marine or fresh- 

 water sponges in fluid, the best material is strong spirit, or water 

 with a considerable excess of undissolved salt in it, but never alum. 

 Jars or pickle and fruit bottles, well corked and sealed, or tied 

 over with bladder, are the best vessels for the purpose." 



Eising a little higher in the scale of life, little has been done 

 with our fresh-water polyps, whether the simple hydra-like forms 

 or the more complex fresh-water bryozoa. Great reputations have 

 been made by the study of such creatures in Europe, — and in a 

 land of streams and lakes like this, much could certainly be done 

 in collecting new forms, and adding to our knowledge of the ha- 

 bits and range of organization of the fresh-water radiates. These 

 animals should be sought in lakes and streams, especially on sub- 

 merged wood, fresh-water shells, and the leaves of aquatic plants. 

 They may easy be kept in water for examination, and careful draw- 

 ings should be made of their forms and internal structures as seen 

 under the microscope. It is difficult to preserve them ; but I would 

 recommend immersion in glycerine or the method above given for 

 sponges, as likely to succeed. 



The mollusks also offer tempting fields of inquiry, more culti- 

 vated than those formerly noticed, but still having large promise. 

 Many species of unio, alasmodon and anodon, exist in our river, 

 most of them no doubt identical with species described by Ameri- 

 can naturalists, but some perhaps new, and many requiring more 

 careful study as to their habits, reproduction, and the real limits of 

 species and varieties. The univalve mollusks are also very nume- 

 rous, both in the waters and on the land, and require study, more 

 especially in relation to the animals as distinguished from the 

 empty shells. Such studies demand patience and nicety, and 

 would be greatly aided by vivaria, in which these creatures can 

 be easily kept alive and examined at leisure. Mr. Billings, one 

 of our members, has done some work in this field, portions of 

 which have appeared in the Canadian Naturalist. Prof. Hall 

 will bring before us this winter some interesting facts respecting 



