68 



The Canadian Field-Naturalist. 



Vol. XXXV 



CANADIAN SPHAERIIDAE. 

 By the Hon. Mr. Justice Latchford. 

 (Confiiiurd f.om Vol. XXX fV.. p. 71.) 



21. MUSCl'LirM SECriUy.Priiue. This 

 >;peeies resembles t, uncatuin in the al)rtipt- 

 iiess of the posterior margin, hut is a 

 smaller sheD. Its anterior margin is shorter 

 and more rounded, and the lines of growth 

 are deeper and more distinct. T^ie valves 

 are thicker, less glossy, and paler within 

 and without. It occurs on a muddy bot- 

 tom in St. Louis Dam, inside the viaduct, 

 and probably outside it; and in the pond 

 north of the electric railway station at 

 Britannia Highlands. 



22. MUSCULIUM WINKLE Yl Sterki. 

 The ponds east and west of Bi-itannia 

 formed by the Ottawa at high water aiid 

 several of the small streams in Nepean ])ro- 

 duce this pretty little shell in considerable 

 numbers. It was described in the Nauti- 

 lus (XXIII, 66) from specimens found by 

 the Rev. H. W. Winkley near his home at 

 Danvers, Mass., and at Old Orchard, Me. 

 From this indefatigable collector and stu- 

 dent of the Sphaeriidae I received from 

 time to time during many 3'ears delightful 

 letters and fine sets of rare or newly des- 

 cribed species. WiuMeiji resembles seeuris. 

 The first specimens from the vicinity of 

 Ottawa sent to Dr. Sterki were thought to 

 be a variety of that species and were mark- 

 ed M. seeuris cardissum. It is, however, 

 as the description states, higher than seeu- 

 ris with more rounded outlines, the hinge 

 margin is more curled, and the difference 

 of size and shape between the anterior and 

 posterior parts is less marked; in seeuris 

 the posterior part is more truncate and less 

 obliquely so to the dorso-ventral line. 



2:1 Mi:SCULIUM PARVUM Sterki. In 

 the same number of the Nautilus (p. 67), 

 Dr. Sterki distinguished and described an- 

 other shell usually confused with seeuris. 

 The types were from Ohio, but the species 

 has a -^vide distribution. It is not uncom- 

 mon in the Britannia i>onds, but has not 

 been found elsewhere near Ottawa. It is 

 smaller than seeuris, the superior margin is 

 less curved, the posterior more rounded 

 and more oblique; the surface shining, the 

 shell colourless, the siphons are said to be 



much shorter, connected, and colourless, 

 while in seeuris they are yellow to orange, 

 or salmon, or reddish. The Britannia 

 shells correspond in size with the average 

 measurements of the tyi)es: long. 4.7, alt. 

 4. diara. 2.8 mm. 



24. MUSCULIVM PARTUMEIUM Say. 

 In Heron's list of Ottawa MoUusca (Trans. 

 O. F. N. v., I. 40) this shell is included 

 with a (f)- The indentification was prob- 

 ably correct as the species is not uncom- 

 mon in many small ponds south of the 

 city, near where Heron lived. When 

 mature it exceeds truneatmn in size, is 

 brightei- in color, more inflated and with 

 higher beaks. It is not as large as jayeii- 

 se, nor so pinched in before and behind the 

 hinge. From our rosaeeum it differs in 

 the greater projection of the beaks, and in 

 being more distinctly yellow in color. 



This species has a very extensive range 

 east of the Rocky Mountains, and what is 

 now considered to be a variety of it — M. 

 variable Prime — occurs as far south as 

 Floi-ida. In Canada the shell has been 

 found in Manitoba and at several places 

 in Central Ontario. I have fine specimens 

 .from Hamilton collected by Mr. A. W. 

 Hanham, and several from Humber Bay, 

 Toronto. 



25. MUSCULIUM JAYENSE Prime. 

 This shell, while not as large as transver- 

 .'ium, is much more beautiful, and is more 

 characteristic of the genus. It is of a 

 brighter color, shorter, higher, more in- 

 flated and more jnnched in before and be- 

 hind the hinge, giving the central area of 

 the' shell, as will be noticed in the figure, 



Fig. 5. — M. jayense ■ 1'/2 



a boldly triangular contoui'. The species 

 has a wide distribution over the middle 

 West and extends into Michigan, but does 



