10 



Hombtrypella dubia (Cumings and Galloway). — Thin, bifoliate expansions 

 are found in the Bythopora meeki zone of the Streetsville member, which can 

 without doubt be referred to this species. This is a rather interesting occurrence, 

 since, heretofore, the species has not been found in rocks higher than the 

 Arnheim in Indiana and Ohio. See Plate VII, Figure 10. 



Hotnotrypella expansa, sp. nov. — See page 25. 



Homotrypella hospitalis (Nicholson). — This species is abundant in the 

 Credit River section, being found in all three members of the Richmond formation. 

 It is most abundant in the Meadowvale member. The species may form very 

 regular hemispheric masses as in Plate V, Figure 2, or irregular lobate masses 

 as in Plate V, Figure 1. The smallest specimen measures 16 millimetres in 

 diameter by 12 millimetres in height; the largest specimen is twice this size. 

 In the Ohio valley, //. hospitalis occurs in all the members of the Richmond 

 formation. 



Homotrypella hospitalis pecidiaris, var nov. — See page 25. 



Mesotrypa patella (Ulrich). — One good example of this species was found in 

 the Streetsville member. It agrees with the type from the Whitewater of the 

 Ohio valley in all details except one: the maculae, consisting of larger tubes 

 than the average, which are characteristic of M. patella, have not been seen in 

 the Credit River example. If the absence of the maculae is found, after an 

 examination of more material, to be a constant feature of the Streetsville form, 

 a new variety would be justified. See Plate V, Figure 9. 



Monotrypella curvata, sp.no v. — See page 26. 



Monticulipora parasitica multipora, var nov. — See page 27. 



Rhinidictya cf. parallella (James). — Abundant specimens of a crypto- 

 stomatous bryozoan are found in the Erindale member on the Credit river. 

 They are very close in their relationships to R. parallella of the Southgate member 

 of the Eden of the Ohio valley, but as no well-preserved specimens were obtained, 

 and as they are characteristic of a much higher zone, it is thought best not to 

 refer them too definitely to James' species. 



Rhombotrypa quadrata (Rominger). — This species and Constellaria poly- 

 stomella are abundant in and confined to the Columnaria reef in the Meadowvale 

 member. This is an interesting fact, since both species are found in all the 

 members of the Richmond formation, in the Cincinnati basin and on Manitoulin 

 island. See Plate IV, Figure 5; Plate VI, Figure 4. 



Stigmatella crenidata, Ulrich and Bassler. — Typical representatives of this 

 species are found in the Erindale formation. The Credit River forms differ 

 from those described by Parks and Dyer from the Humber river at Toronto, 

 which they ascribe to the same species, in that the walls of the former are 

 inflected by the acanthopores, to a greater extent. The Humber River forms 

 are probably forerunners of S. crenulata, but should at least be given a new 

 varietal name. In Ohio, according to Shideler, S. crenulata is confined to the 

 Waynesville member of the Richmond. See Plate IV, Figure 6; Plate VII, 

 Figure 8. 



Stigmatella hybrida, sp. nov. — See page 27. 



