113 



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

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

 opportunity to examine, refers Cribrilina 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 H. 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 natm-ally belongs to the familly Bicellariidae, I 

 am unable to adopt Mac Gillivray's family. 



Brettia Dyster. 



? Maplestonia, Mac Gillivray. 



(PI. IV, figs. 9 a— 9 b). 



The distal wall is not angular; ocecia and avicularia wanting; the colonj' with 

 single-rowed zocecia. 



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 colonj' of M. simplex 

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

 strongly calcified ciyptocyst 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 Catenaria in its whole mode of growth. 



The form, which Waters* has named Brettia frigida 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 Bugula qvadridentata, which is only a growth-form or variety of 

 Dendrobeania Murrayana. This species sometimes appears with multiserial (4 — 26 

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

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

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

 Bugula as defined here, the distal wall in D. Murrayana is furnished with a 

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



' 76, pp. 60—61. ^ 38 a, p. 479. ' 67, p. 92. * 114, p. 51. 



