282 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



Some internodes in most colonies of this species are distinctly club- 

 shaped, and these usually exhibit a zooecial attachment pore. 



Occurrence. — Silurian, Island of Gotland. Buildwas beds of Wen- 

 lock shales, England. 



Cat. No. 43,125, U. S. N. M. 



ALLONEMA MONILIFORME (Whiteaves) and var. AGGREGATUM 



new variety 



(Plate LXV, 14; Plate LXVII, 9) 

 1891. Stomatopora moniliformis Whiteaves, Cont. to Canadian Paleon- 

 tology, vol. I, p. 212, pi. 28, fig. 10. 



Original Description. — " Polyzoary minute, creeping, attached by 

 the whole of its under surface to some foreign object, very slender 

 and fragile, consisting of a few irregularly disposed but more or less 

 divergent rows of single cells, which, though uniserial, occasionally 

 throw off lateral buds consisting of one or more cells, and which may, 

 as in the specimen figured, proceed from a central or subcentral 

 irregular aggregation of cells. Cells moderately convex, elliptical 

 in marginal outline, averaging half a millimetre in length, about one 

 third longer than broad and placed end to end : apertures of the 

 cells nearly terminal, extremely minute, simple and consisting of 

 mere rounded perforations in the cell wall. Surface smooth." 



The above description brings out several points showing that the 

 species cannot be a Stomatopora. That both the description and 

 figures given by Whiteaves faithfully record the facts can be attested 

 by the senior author of this paper who, in 1890, saw the four speci- 

 mens upon which the species was shortly thereafter established. At 

 that time the latter failed to recognize the true affinities of the speci- 

 mens, but now, since we have studied all the known Paleozoic forms 

 of this peculiar type of Bryozoa, we have not the least hesitation in 

 pronouncing Stomatopora moniliformis a species of Alloncma. Spe- 

 cifically it is closely allied to our A. botelloides, but differs in the 

 slightly greater average width and more bead-like form of its inter- 

 nodes. The small, subcentral aggregation of vesicles is another fea- 

 ture that may assist in separating the species from the Silurian type 

 of the genus. 



Variety AGGREGATUM new variety 



Under this name we propose to distinguish a variety of A. monoli- 

 forme that is represented in the Ulrich collection by a single, well- 

 preserved example from the Hamilton formation in Genesee county, 

 New York. It is a patch about i cm. in diameter, attached to a small 

 coral, and consists, as may be seen in plate lxvii, 9, of a closely 



