26 
outside witli veiy fine pores; no inner calcareous plate; tlie fourth 
pair of loculi (vittae Busk) very narrow, elongated, seated on the 
front wall; in the old zooecia the closure is performed hy 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 ooecia, generally without 
pores; poi-echamhers or rosette-plates with several pores. To this 
family I refer the following genera, which shall he characterized in 
a later work; Mucronella (with the species M. Peachii, M. vario- 
losa, M. ahyssicola, M. diaphana, M. spinosissima etc.), Peristomella 
n. g. (P. coccinea, P. præstans). Exochella ZwW., AnartJiropora (A, 
monodon), Microporella, Porella and Mastigophora {M. Dutertrei, 
M. Alderi, M. spinifera, M. dædala etc.). 
Smittiidae. Hyperstomial ooecia, generally with pores; both 
the distal wall and the lateral walls with a numher (ca. 4—8) of 
single-pored rosette-plates. Besides the genus Smittia whose ori¬ 
fice is provided with two siender hinge-teeth and a median extra- 
opercular teeth, all the species with single-pored rosette-plates, hi- 
therto referred to Schizoporella and Lepralia, must he 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 ooecia 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 faet that Bifaxaria denticulata Busk, of which 
species I have been able to examine a number of exemplars, is 
nearly related to Porina horealis 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 
