VINE : BRITISH PALEOZOIC CTENOSTOMATOUS POLYZOA. 89 
The American forms described by Nicholson and Etheridge are 
the following : 
Ascodictyon fusiforme, Nicholson and Etheridge, Jim. 
1877. Ann. Mag. Nat. Hist,, ser. 4, vol. xix., pp. 463-464, pi. 19, 
figs. 7-8. 
Unfortunately this is the type species of the authors, and after 
the most careful investigation and study I am imable to locate the 
present form or quote it as an ally of any recent Ctenostomatous 
Polyzoa. The species is well described, and the authors felt their 
own difficulties when attempting to place it, even provisionally, as an 
ally of any known Polyzoon, either recent or fossil. "Our A. fusi- 
form?" they say, (p. 467) " certainly presents a close superficial 
resemblance to the creeping base of Anguinaria (JEtea) spatulata, but 
in the absence of any evidence in the fossils of the existence of erect 
cells with distinct apertures for the polypides, it would be hazardous 
to regard this suggestion as being more than a conjecture." Certainly 
A. fusiforme in general outline closely resembles the stolons of Mtea 
anguina* as figured by Hincks, and the Devonian fossil may be super- 
ficially compared with the iEtea group, but I do not think any real 
affinity between them could be established. Amongst some examples 
of the fossil, encrustations on the stems of Crinoids, already referred 
to as given to me by Mr. John Young, forms similar to those described 
by Messrs. Nicholson and Etheridge, may be detected, thus establish- 
ing a generic affinity between the American Devonian, and the Scotch 
Carboniferous forms, but beyond this I cannot go. The American 
species is described as rare and adherent to Spirifera mucronata, 
Conrad, Middle Devonian, Ontaria ; the Carboniferous forms are 
generally adherent to Crinoid stems from the Calderwood and Boghead 
Shales, Scotland. 
Ascodictyon stellatum, Nicholson and Ethridge, Jun. 
1877. Ann. Mag. Nat. Hist., ser. 4, vol. xix., pp. 464-465, pi. 19, 
figs. 1-6. 
There is the closest resemblance between this and the Silurian 
species A. siluriense, already described, but as there are special 
* Brit. Mar. Polyzoa, vol. ii., pi. 1. 
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