68 



The Canadian Field-Naturalist. 



Vol. XXXV. 



CANADIAN- SPHAERIIDAE. 

 By the Hon. Mr. Justice Latchford. 



[Continued f.om Vol. XXXIY.. p. 71.) 



21. MUSCULIUM SECITRIS.Prime. This 

 species resembles i.nncaium in the abrcipt- 

 ness of the posterioi- maryiii, but is a 

 smaller shell. Its anterior margin is shorter 

 and more rounaed, and tiie 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 [)ond 

 north of the electric railway station at 

 Britannia Highlands. 



22. MUSCULIUM WINKLEYI Sterki. 

 The ponds east and west of Britannia 

 formed by the Ottawa at high water and 

 several of the small streams in Nepean i>ro- 

 duce this pretty little shell in considerable 

 numbers. It was described in the Naiiti- 

 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 years delightful 

 letters and fine sets of rare or newly des- 

 cribed species. Winkleyi resembles securis. 

 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. secuns cardissum. It is, however, 

 as the description states, higher than secK- 

 ris with more rounded outlines, the hinge 

 margin is more curled, and the difference 

 of size and shax)e between the anterior and 

 posterior parts is less marked ; in securis 

 the posterior part is more truncate and less 

 obliquely so to the dorso-ventral line. 



23. MUSCULIUM PARVUM Sterki. In 

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

 Dr. Sterki distinguished and described an- 

 other shell usually confused with securis. 

 The types w^ere from Ohio, but the species 

 has a wide distribution. It is not uncom- 

 mon in the Britannia ponds, but has not 

 been found elsewhere near Ottawa. It is 

 smaller than securis, 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 securis they are yellow to orange, 

 or salmon, or reddish. The Britannia 

 shells correspond in size Avitli the average 

 measurements of the ty])es : long. 4.7, alt. 

 J-. diam. 2.8 mm. 



24. MUSCULIUM PARTUMEITTM Say. 

 In Heron's list of Ottawa MoUusca (Trans. 

 0. F. N. C., 1. 40) this shell is included 

 with a (?). 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 truncatum in size, is 

 brighter 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 rosaceum it differs in 

 the greater projection of the beaks, and in 

 being moi-e 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 

 Florida. In Canada the shell has been 

 found in Manitoba and at several places 

 ill 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- 

 sum, is much more beautiful, and is more 

 characteristic of the genus. It is of a 

 brighter color, shorter, higher, more in- 

 flated and more pinched in before and be- 

 hind the hinge, giving the central area of 

 the sliell, as will be noticed in the figure. 



Fig. 5. M. jayense 



1'/2 



a boldly triangular contour. The species 

 has a wide distribution over the middle 

 West and extends into Michigan, but does 



