184 
G. W. Lee — Trepostomata. 
description is nevertheless very good, and suffices for the identification of topotypes. 
The more important part of his diagnosis is as follows :— 
“ Polypier de forme tres-variable, offrant ordinairement l’aspect de grosses branches 
irregulierement bosselees, h extremites obtuses et arrondies. Quel que soit cependant 
le diametre de ces branches, le polypier proprement dit n’en occupe qu’une faible 
partie, qui se presente sous la forme d’une couche tres-mince, d’une epaisseur egale dans 
toute son etendue, et n’atteignant generalement pas au dela d’un demi-millimetre. 
Les polypierites sont done extremement courts et ne possedent pas cette disposition 
rayonnante qu’ils affectent dans l’espece precedante m [that is, “ Monticulipora tumida ”]. 
The last sentence is significant and shows that de Koninck recognized the essential 
difference between his species and the Trepostomata typified by “ Monticulipora tumida ,” 
namely, that here the zoarium is not made up of radiating fasciculated tubes. 
Specimens from Vise, agreeing in every respect with de Koninck’s description, are 
preserved in the British Museum (Natural History). Most of them [55524, D. 20613 
to D. 20617] are decalcified, as is usually the case with Vise materials, but fortunately 
specimen D. 20612 is well preserved and it was therefore selected for slicing. The 
internal features of that specimen are an exact reproduction of those shown by the 
English materials. Externally it appears as a slightly flattened branch 15 mm. by 
10 mm. across its two diameters ; but it really consists of two layers, suggesting the 
beginning of a complex zoarium such as that of the Wetton specimen figured, plate xvi., 
fig. 21. 
Although in most cases the re-description of a species should admittedly rest on the 
examination of the holotype, it is quite possible that in this particular instance the clear 
internal features shown by the well-preserved topotype could not have been observed in 
the original, which is obviously decalcified. 
VII.— Remarks on Distribution and Evolution. 
The species described in this memoir do not by any means constitute the whole of 
the British Lower Carboniferous trepostomatous fauna. The forms referred to in the 
various comparative remarks, as well as a number of others macroscopically studied, are 
represented by single or indifferently preserved specimens, the detailed description of 
which may be fitly deferred until more suitable materials can also be examined. Yet, as 
1 16, p. 147. 
