﻿ULRICH BASSLER] REVISION OF PALEOZOIC BRYOZOA 



intervals between which the) are wanting; in ramose E01 

 the) are developed in the extreme outer region. 



Genus Heterotrypa Nicholson 



Cumings, in a recent revision of the genera Dekayia, Dekayella, 

 and Heterotrypa? arrived at the conclusion that they represenl one 

 and the same generic type, lie also believes that Ulrich's identifi- 

 cation of Monticulipora frondosa, the genotype of Heterotrypa, \< 

 incorrect. According to his conception, Monticulipora frondosa is 

 founded on a species of Homotrypa that occurs as a comparatively 

 rare fossil in the upper beds of the Lorraine formation. 



To determine the species Heterotrypa frondosa. the genotype of 

 Heterotrypa, we sought and succeeded in securing .specimens from 

 D'Orbigny's type lot and also a fragment of Edward and Haime's 

 figured specimen of Chcctetes frondosus. For the first of these we 

 are greatly indebted to Dr. M. Boule of Paris, and for the second 

 to Dr. H. Douville of the Ecole cles Mines, Paris. To assure us as 

 much as possible of the authenticity of the latter, Dr. Douville 

 marked out on a sketch of Edwards and Haime's figure of this 

 species the exact place from which the fragment sent us was nipped. 

 Consequently, we now consider ourselves well equipped to settle 

 beyond dispute the question of what D'Orbigny really meant by 

 Monticulipora frondosa. 



As can be readily seen from the views of thin sections of this 

 fragment given on plate xi, the species, instead of being a Homo- 

 trypa, as claimed by Cumings, is the same as that so recognized by 

 Ulrich more than twenty years ago. 



The two specimens of Monticulipora frondosa selected by Dr. 

 Boule from D'Orbigny's type lot are also of the same species as that 

 represented by Edwards and Haime's figured specimen. The syn- 

 onomy of Heterotrypa frondosa given by Ulrich in his work on the 

 species, and later by Nickles and Bassler, therefore stands with 

 Cumings' new name. Dekayia perfrondosa, as an additional synonym. 



As to the value of the three genera discussed by Mr. Cumings, we 

 do not deem this the proper place to go into the subject in detail. 

 However, we still consider the three genera distinct and very con- 

 venient in classification if not wholly natural groups. It is true that 

 Ulrich some years ago expressed the idea of combining the three 

 genera, but this was at a time when Dekayella was the only genus 

 of the three of which species were known in the Mohawkian and 



1 Amer. Geologist, xxix. 190J. pp. 197-217. 



