2G5 



ftilvus, StrohUa labijrintJdca, Piiim contracta, Say, Succinea ovalis, and 

 Tchennophorus carolinensis, Base. 



We were absent from the city when the excursions were held to. 

 Buckingham and Casselman, but on these occasions the branch was, 

 represented by Mr. Harrington. Little worthy of particular mention 

 was observed at Buckingham, but at Casselman an important addition, 

 was made to our lists in the large and handsome Mesodon thyroi- 

 des, Say. 



Considerable independent work was done by individual members 

 of this section when business cares permitted. On the 3rd and 4th of 

 September a tour was made along La Peche River, in the County of 

 Ottawa, from its mouth to its source. As far back as Masham post 

 office, the stream, flowing in a gravelly bed, often strewn with boulders, 

 appears to contain only two shells, Unio complanatus and Pkysct 

 heterostropha, the latter very large. Before reaching Masham a visit 

 ■was made to a small and in part shallow lake on the right of tlie road 

 leading up the valle^'. It is locally known as Gauvreau's Lake, being^ 

 named, as is customary in the Lauren tides, after a neighbouring settler. 

 It fairly teems with moUuscan life. Four species, howevei, found com^ 

 mon there on July II, 1881 : Annicola porata, Say, Limncea desidiosa. 

 Say (a small but beautiful variety), FUmorbis deflectus, and Spairium 

 sulcatum, Lamk., had almost entirely disappeared. Cainpeloma decisum 

 was rare as on the occasion of the former visit to the lake, and a large 

 fine variety of Planorhis trivolvis very common. Unio complanatuSy 

 U. luleolus, Lamk., Aiiodoi.ta fragUi>i, Lamk., and A. lacustris, Lea, 

 occurred in the shallows in great abundance, notwithstanding the im- 

 mense numbers destroyed by muskrats, as bore witness the large heaps 

 of empty shells at short intervals along the shore. In this and other 

 lake's the muskrats tear off one valve of the fragile anodontas, but the 

 thick shelled species, as well as margaritanas and unios, they treat in a 

 different manner, breaking off invariably a small portion of the lower 

 third of the posterior margin. It is not improbable that they then 

 extract the juices of the animal by suction, and when the adductor 

 muscles relax and the valves open the firmer parts become easily 

 accessible. Where thin andontas are rare and occur in company with 

 numerous unios, as at several points along the Ottawa, they are treated. 



