38 GEOLOGICAL AND NATURAL HISTORY SURVEY OF CANADA. 



single series between the zocccia, yet it is rot uncommon to notice 

 a double row for a short distance. An obscure radial an-angement 

 is noticeable about certain points whei-c the interstitial vesicles are 

 more numerous than elsewhere, without, however, at any time, being 

 in sufficient numbers to justify being (^-alled " maculae." These are six 

 mm or moie apart. 



Vertical sections are, perhaps, even more characteristic since in 

 these the loose construction already mentioned is very striking. In these 

 the zoa?cia appear as long irregular tubes crossed at variable intervals 

 (generally of one millimetre) by very delicate horizontal diaphragms ;. 

 the vesicles assume all sorts of shapes, but are always remaj-kably high, 

 and the walls between both the vesicles and the zooecia have that 

 peculiar granular structure noticed, in palaeozoic bryozoa, only among 

 the Geramoporidcv^ and Fistuliporidce.''^ The section also presents some 

 evidence of minute connecting foramina in the walls between the 

 zooecia and vesicles. 



In F. laxata I see what may be called the beginning of the Fistuli- 

 poridoe. As I have elsewhere stated, it is my belief that the Fistuli- 

 poridce and Ceramoporida' had a common origin, and in this species 

 we see much to remind us of the latter group of bryozoa. Tangential 

 sections of it are not much unlike those of certain species of Ceramo- 

 porella, but the long tubes shown in vertical sections and the, though 

 rude, vesicular character of the interstitial spaces are important 

 differences. As a rule the zooeial tubes are short in the Ceramoporidoi^ 

 still in Chiloporella, Anolotichia and certain forms of Crepipora, they 

 are long enough to bear comparison with F. laxata. It is with these, 

 probably, that this prototype tinds its nearest relatives, but Ceramo- 

 porella (despite the differences mentioned) may prove a closer ally.y 



Since the above was written, I have had occasion to look over some 

 of my unworked Minnesota bryozoa. Among the material I found 

 several examples of a species differing in no respect from the Manitoba 

 specimen described, save that the zoaria do not exceed seventy mm. in 

 diameter and twenty mm. in height. These specimens enable me to add 

 that the lunarium forms a prominent "lip" at the surface, and that 

 here the vesicles are usually open — a feature probably due to attrition, 

 since they are closed {i.e. the interstitial spaces appear solid) over the 

 best preserved portions of one of the examples. 



* The "granular" structure of the walls in species of Monticulipora is diflferent. 



i A new genus ought, perhaps, to be established to include F. ? laxata and one or two species 

 known to me. Of the latter, one (a common form in the upper beds of the Hudson River or 

 Cincinnati group at Wilmington, III.) is described provisionally as Crepipora ? epidenri'ita in my 

 report on Bryozoa for vol. viii., 111. Geol. Surv. Repts., now in press. I prefer, however, to await 

 the completion of my studies in this large and difficult group before proposing the genus. 



