40 The Ottawa Naturalist. [June- July 



cardinal auriculations, the thickened border in the interior of brachial 

 valve, and the sharp prominent ridges along the axial margins of the 

 adductor muscle scars. 



Horizon and locality: Lower Trenton limestone; Wolfe Island, 

 Ontario. Stations 224?; '226, and 308. 



.EXPLANATION OF PLATE. 



PRASOPORA SIMULATRIX ORIENTALIS. 



Figures 1-, 2 Vertical and tangential sections, X 10, of an average specimen. 

 Queen's University Paleontologic Museum No. 1263. 



HALLOPORA VARIA. 



Figures 3, 4, 5 Tangential, vertical and transverse section, X 10, of the 

 holotvpe. Queen's University Paleontologic Museum No. 1272. 



Figures 6, 7 Two of the plesiotypes, natural size. Queen's University Paleon- 

 tologic Museum No. 1270. 



HALLOPORA OBLIQUA. 

 Figures 8, 9 Vertical and transverse sections, X 10, of one of the cotypes. 

 Figures 10, 11 Two of the cotypes, natural size. Queen's University Paleon- 

 tologic Museum No. 1276. 



PLECTAMBONITES CURDSVTLLENSIS. 

 Figure 12 A pedicle valve showing the faint mesial sinus commonly observed 



on the shells thus identified. 

 Figure 13 The interior of a brachial valve from the same locality. Queen's 



University Paleontologic Museum No. 1269. 



RAFINESQUINA DELTOIDEA. 

 Figure 14 A pedicle valve. Queen's University Paleontologic Museum No. 1262. 



PLECTAMBONITES PUNCTOSTRIATUS. 

 Figures 15, 16, 17 Three of the cotypes, pedicle valves. Queen's University 

 Paleontologic Museum No. 1277. 



NOTES ON THE LAND MOLLUSCA OF DE GRASSI POINT, 

 LAKE SIMCOE, AND OTHER ONTARIO LOCALITIES. 



By'E. M. Walker, E-R.S.C, University of Toronto. 



{Continued from page 22.) 



22. Zonitoides arbor ea (Say). The commonest of all our land 

 Mollusca, occurring in the woods everywhere, from the tamarack 

 swamp to the hardwood forests. Toronto, May-October; De Grassi 

 Point, April 27th September; Go Home Bay, July 15th-17th; Giant's 

 Tomb Island, July 20th; St. William's, September 3rd. 



23. Zonitoides exigua (Stimpson). This minute ribbed species 

 is common at De Grassi Point under leaves and rubbish in the woods. 

 It was also taken at Go Home Bay and the Giant's Tomb Island. 



24. Zonitoides milium (Morse). Toronto, De Grassi Point and 

 the Giant's Tomb Island, not rare under leaves in woods. 



