﻿ULRICH BASSLER] REVISION OF PALEOZOK BRYOZOA -V 



our last published conception of the genus is affected b) the division 

 of the Trepostomata into the two sections discussed on a preceding 

 page. In the first of these two primary divisions, the Amalgamata, 

 the walls of adjoining zooecia are fused together, or, using a term 

 more commonly employed, amalgamated. In the second division, 

 the Integrata, the walls remain separate, and divide readily along 

 the sharp, dark line which marks the contact between adjoining 

 tubes. Xow. the type of Leptotrypa clearly belongs to the Hetero- 

 trypidce, which are good Amalgamata, while other species referred to 

 the genus have the wall structure characterizing the [ntegrata, so 

 that a splitting up of the genus is necessitated on that -round alone. 

 Besides, we have come to pay more attention to the tabulation of the 

 tubes and with gratifying results in the way of natural classification. 

 In accordance with the facts brought out by our recent studies, 

 we had to restrict Leptotrypa very nearly to the limits originally 

 assigned to the genus in 1883. As revised, the genus includes only 

 three or four parasitic species. L. minima (Jlrich, L. ornata Ulrich, 

 L. clavacoidea (James), and several undescribed species which form 

 thin expansions made up of tubes in which diaphragms are very few 

 or wanting. This restriction leaves a number of species which find 

 a place naturally enough under Amplexopora (e. g., L. Hliosa 

 (D'Orbigny). L. petasiformis (Nicholson), etc.), but for a larger 

 number new generic groups are here established. Cyphotrypa is 

 necessary for the reception of the massive Heterotrypidce with well- 

 developed diaphragms, while species of the type of L. clavis and L. 

 irregularis Ulrich are referred to the new genus Stigmatella. 

 These removals will be further discussed under their respective 

 genera. 



Genus Cyphotrypa new genus 

 Massive Heterotrypidce. Zocecial walls thin, amalgamated, the 

 central portion light-colored ; tubes prismatic, with numerous well- 

 developed diaphragms ; mesopores wanting, acanthopores well devel- 

 oped. 



Genotype: — Leptotrypa acervulosa Ulrich, a characteristic Tren- 

 ton fossil in Iowa, Minnesota, and Kentucky. 



As stated in our remarks on Leptotrypa. the restriction of that 

 genus to species agreeing strictly with its type necessitated the erec- 

 tion of a new genus for the massive and well-tabulated Amalgamata 

 that previously had been referred to Leptotrypa. The importance of 

 the characters that distinguish these massive forms from the typical 

 species of Leptotrypa. and consequently the desirability of the sepa- 

 ration, became more and more evident as they grew in number. Up 



