92 W. M. Bale: 



Levinseii leiuarks that the sub-marginal V>and is douljtless due to 

 a regeneration; tlie fact, however, that it is always present, and is 

 constant in its position, seems in itself sufficient to negative that 

 view. It is. like the marginal liand. a thickened ridge surround- 

 ing the hydrotheca internally, and it not iinconnnonly corresponds 

 to a slight external constriction. It varies in the extent to which 

 it is thickened. Ijeing sometimes feebly developed, especially in the 

 newly-formed hydrothecae; and in any case, it is somewhat less 

 robust than the border-thickening, at least in the vicinity of the fotir 

 marginal points. The marginal band is at least as strongly ma)-kcd 

 at these points as elsewhere, the secondary band does not usually 

 form pionounced points like the marginal one, but is more bluntly 

 rounded at those positions. 



The hydrotheca is without a fully-developed diaphragm. l)ut there 

 is an internal perisarcal ring just above the base. Higher up there 

 is a zone of thinly scattered bright points. 



EXPLANATION OF PLATES. 



Pl-\te XT. 



Fig. 1. — Orthopyxis caliciilata (Hincks). 



Fig. '1. — Orthopyxis macrogona (Von Lendenfeld). 



Fig. "5. — Orfhopy.rh plat ycnrpo . n. sp. 



Fig. -i. — Orthopyxis a/n/alafa. n. sp. 



Fig. 5. — Orthopyxis WiJxoni, n. sp. 



(All magnified -id diameters). 



Plate XII. 



Fig. 1. — Orthopyxis caliculata (Hincks). 



Fig. 2. — Orthopyxis macrogona (Von Lendenfeld). 



Fig. 3. — OrfTiopyxis plafycarpa, n. .sp. 



Fig. 4. — Orthopyxis angulata, n. sp. 



Fig. 5. — OrtJiopyxis Wilsoni, n. sp. 



(All magnified 20 diameters). 



