64 



The Canadian Field-Naturalist 



[Vol. XXXIII 



found. Each lot should be kept separate and num- 

 bered. A brief record under the same number on 

 a field card or in a note book should be made. If 

 the shells are stained they may be cleaned by 

 placing them in a bottle containing sharp sand and 

 soapy water. On no account should an acid be 

 used. By rotating the contents the shells will be 

 cleaned on the outside. Mere drying out then 

 suffices, when the shells are mmute; but when large, 

 the animals must be removed after boiling, or ren- 

 dered innocuous by immersion overnight in a five 

 to one dilution of formalin by far the more rapid 

 process, as the tying or wrapping of each shell is 

 not then necessary. When thoroughly dried, after 

 treatment with formalin, the largest shells will not 

 gape, or cause offence by their odor, and may be 

 placed in the collector's cabinet. 



As he examines his specimens he will observe that 

 they fall naturally into three groups or genera. By 

 far the greater number ordinarily found are minute 

 shells, triangular in outline, very unequilateral, and, 

 with rather sharp terminal beaks. They resemble 

 small peas, and belong to a genus fittingly called 

 Pisidium. 



Fig. 1 

 Sphaerium sulcatum X 1 Vz-^ 



Other shells will be noticed which are larger, 

 less inflated, though never exceeding half an inch 

 in length; and usually more delicate and fragile. 

 They bear little caps on the beaks, separated from 

 the aftergrowth by a distinct furrow, and form the 

 genus known as Musculium. 



Still larger shells, often adorned with distinct 

 color bands, denoting periods of arrested develop- 

 ment, and others of no greater size than some 

 Musculia, but of heavier texture, and as a rule more 

 deeply striated, beeir Sphaerium as their generic 

 name. The term was devised by Scopoli, an Italian 

 naturalist and chemist in 1777. It has priority to 

 C])clas (Brugaiere, 1789); and Sphaeriidae, ac- 

 cording to the laws of modern zoological nomen- 

 clature has replaced Cydadidae as the proper desig- 

 nation of the family to which the little mussels 

 belong. 



iFor tliis ancl the other figures in tlie text I 

 am under the greatest obligation to my friend Dr. 

 Bryant Wallier of Detroit, Mich. 



1. Sphaerium SULCAIUM Lamarck, the largest 

 of the genus in the species most commonly observed 

 in the vicinity of Ottawa. It was described in 1818 

 by the famous French naturalist in his "Animaux 

 sans Veriebres," from specimens obtained in Lake 

 Champlain. In the same year Thomas Say de- 

 scribed the shell in the American edition of Nichol- 

 son's Encyclopedia as C^clas similis, and Say's 

 name may have priority. However, the Lamarck- 

 ian name is more generally adopted, and is that used 

 in the Club's lists. 



5. sulcatum is the largest of the genus. It is 

 oval in outline; distinctly, rather than deeply, striate; 

 and, when adult, is usually banded with concentric 

 dark lines, marking periods of arrested development 

 such as occur every winter. The body color is of 

 varying shades of grey or brown. Young shells 

 are almost white. 



But one other species, restricted in Canada, so far 

 as known, to a single locality near Ottawa, ap- 

 proaches this in size. All bivalves found else- 

 where that are about three-quarters of an inch in 

 length, and have not the corrugated beaks which 

 indicate membership in the family of our large 

 mussels, or Unionidae, may safely be named Sphae- 

 rium sulcatum. 



This species is found in many places within the 

 city limits. It is common in the Rideau river, especi- 

 ally on the muddy bottom of the reach above the 

 islands at Billings' Bridge. In the canal, after the 

 water has been let out, it may be easily collected on 

 the shoal near the right bank west of the Bronson 

 avenue bridge, and anywhere above Hartwell's 

 locks. Very large and perfect shells were obtain- 

 able at one time in the bay at the east end of the 

 small lake below the outlet of Meach lake; but 

 owing to accumulations of sawdust and bark the 

 locality is now barren of this shell, though it still 

 produces sparingly the most remarkable specimens 

 I have ever seen anywhere of Anodonta cataracta 

 Say ( = fluviaiilis Dillw.) and, in addition, Ll;mnaea 

 megasoma, and the shell called Ph})sa lordi in our 

 lists. 



In the Laurentides, north of Meach lake, 5. 

 sulcatum abounds, as in Gauvreau lake and its out- 

 let, near Ste. Cecile de Masham, and in the brook 

 flowing past the orchid swamp still farther north, 

 so well known to members of the botanical branch 

 of the Club, and now, alas! to many others. What 

 a day that was, nearly thirty years ago, when, after 

 visiting the brook and its outlet, Fletcher, Harring- 

 ton and the writer were the first naturalists to dis- 

 cover the sequestered glades where the shy wood 

 nymphs, then literally in thousands, swayed to one 

 another in virgin grace and loveliness! Whoever 

 studies shells should have a mind receptive to the 



