113 



Cribrilinidae, has in a later paper' made this genus into a special family Hianlo- 

 poridae, to which he also, besides some fossile forms, which I Iiave not had the 

 opportunity to examine, refers Cribrilinn monoceros, and Hincks'-' stated already 

 in an earlier work that the two species ought to be united into one genus, and 

 that this genus ought to represent a new family. I cannot admit, however, that 

 there is any relation between the two species which only show the external 

 agreement, that a larger or smaller part of their frontal membrane is covered 

 by branched projections; but whilst these are hollow and originate from the 

 avicularia in //. ferox, they are solid and originate from the lateral margins in 

 C. monoceros. 



They thus show a difference in the only structural feature, which could be in 

 favour of their being united to form one genus. As the genus Hiantopora, accor- 

 ding to the foregoing definition naturally belongs to the familly liicelhiriidae, I 

 am unable to adopt Mac Gillivray's family. 



Brettia Dyster. 



? Maplestonia, Mac Gillivray. 



(PI. IV, figs. 9a-01}). 



The distal wall is not angular; o(vcia and avicularia wanting; the colony with 

 single-rowed zoa-cia. 



I must for the present refer Maplestonia to this genus, as there is nowhere in 

 the diagnosis given by Mac Gillivray a character sufficient to separate it from 

 Brettia. I have been able to examine a small fragment of a colony of M. simplex 

 with some few zociecia, the frontal membrane of which is surrounded by a more 

 strongly calcified cryptocyst with fine lines of growth, which also surrounds the 

 distal wall. Otherwise the two species M. cirrata and M. simplex seem to show 

 great differences, and the first' resembles Catenarin in its whole mode of growth. 



The form, which Waters^ has named llrellia friijida and of which he has 

 been so kind to spare me a little branch, is, as he has himself supposed, identi- 

 cal with Smitt's liiigula qvadrideiitata, wliich is only a growth-form or variety of 

 Dendrobeania Miirraijnna. This species sometimes appears with mulliserial (4 — 26 

 rows), sometimes only with uni- to fourserial branches (H. qvadridentata) and of 

 the last form I have through the kindness of Prosessor Theel, Stockholm been 

 able to examine colonies from Spitzbergcn. In contrast to the species of the genus 

 Bmjnla as defined here, the distal wall in I). Miirraijana is furnished with a 

 multiporous rosette-plate, and in the distal part of each lateral wall, we find two 



' 7G, pp. GO— Gl - :!8a, p. 479. = G7, p. 92. * 114, p. jl. 



