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outside with very fine pores; no inner calcareous plate; the fourth 
pair of loculi (vittae Busk) very narrow, elongated, seated on the 
front wall; in the old zooecia the closure- is performed by three 
calcareous growths (two superior and one inferior) rising from the 
circumference of the orifice and uniting in the centre. 
Mucronellidae n. f. The orifice is provided with a more or 
less developed distal bow; hyperstomial ocecia, generally without 
pores; - porechambers or rosette-plates with several pores, To this 
family I refer the following genera, which shall be characterized in 
a later work: Mucronella (with the species MM. Peachii, M. vario- 
losa, M. abyssicola, M. diaphana, M. spinosissima etc.), Peristomella 
n. g. (P. coccinea, P. præstans). Exochella Jwll., Anarthropora (Å. 
monodon), Microporella, Porella and Mastigophora (M. Dutertrei, 
M. Alderi, M. spinifera, M.dædala etc.). 
Smittiidae.. Hyperstomial ocecia, generally with pores; both 
the distal wall and the lateral walls with a number (ca. 4—8) of 
single-pored rosette-plates. Besides the genus Smittia whose ori- 
fice is provided with two slender hinge-teeth and a median extra- 
opercular teeth, all the species with single-pored rosette-plates, hi- 
therto referred to Schizoporella and Lepralia, must be referred to 
this family. For the reception of all such species I propose a 
provisional genus Monoporina and another provisional genus Poly- 
porina for the reception of all the species of Schizoporella and Le- 
pralia which possess perforated 0o0ecia and rosette-plates with 
several pores. The last genus must together with Ramphostomella 
be referred to another family (Polyporinidae). — Finally I shall 
"call attention to the fact that Bifazaria denticulata Busk, of which 
species I have been able to examine a number of exemplars, is 
nearly related to Porina borealis and that Euthyris obtecta is the 
nearest relative of Calymmophora lucida. In both, the thin and 
fragile cryptocyst is provided with a number of single-pored rosette- 
plates and surrounded by a covering membrane held at a distance 
from the cryptocyst by means of projections from the later, In 
