﻿ULRICH BASSLER] REVISION OF PALEOZOIC BRYOZOA 47 



through some irregularity in growth the normal increase is locally 

 retarded, the zooecia always continue to live until the limit of inn 

 is reached. 



Family (."ALU >P< >KII).K Ulrich 



At present we have no change to suggest in this family nor in tin 

 definition of its genera, except a slight one in Callopora, that is 

 made necessary by the erection of the following new genus upon ( '. 

 crennlata, an untabulated species referred to that genus in 1893 by 

 Ulrich. A new genus, agreeing, apparently, with Callopora in all 

 respects except that is has indubitable acanthopores, is reserved for 

 some future publication. 



Genus Calloporina new genus 

 Callopora (part.) Ulrich, 1893, Geol. Minn., m, p. 275. 



Generic diagnosis. — Zoarium ramose or subramose; zocecia poly- 

 gonal to rounded with walls thin, iridescent, and crenulated in the 

 axial region, slightly thickened and straight in the peripheral zone : 

 mesopores few to numerous : diaphragms wanting in both zocecia and 

 mesopores ; no acanthopores. 



Genotype. — Callopora crennlata Ulrich, Black River and Tren- 

 ton formations of Minnesota, Iowa, and Wisconsin. 



The most obvious distinction between this new genus and Callo- 

 pora. to which the genotype has heretofore been referred, lies in 

 the total absence of diaphragms, not only in both regions of the 

 zocecial tubes, but also in the mesopores. Another character per- 

 taining to all of the species so far observed is the decided crenula- 

 tion of the zocecial walls in the immature region. We have also 

 observed, in all of the specimens of the various species examined, a 

 very pretty appearance in vertical fractures. When such fractures 

 are examined under a hand lens in a good light, a beautiful irides- 

 cence of the zocecial tubes is seen. Of what importance this may 

 be generically cannot be said, but as all of the species show this fea- 

 ture, we see no reason why it should not be included among the 

 generic characters. That this iridescence has some structural signifi- 

 cance is inferred from the fact that it does not occur in such other 

 bryozoa with similarly crenulated walls as Monotrypa undnlata and 

 Anaphragma mirabile. 



So far as known, the genus is limited to the Mohawkian group. 

 Anaphragma. described in this paper, is a very similar new genus, 

 but, having acanthopores, bears the same relation to Batostoma that 

 Calloporina does to Callopora. Calloporina crennlata is rather abun- 



