﻿2S SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 4/ 



otherwise closely related forms, the best interests of classification 

 demand that they be distinguished by a distinct name, whether of 

 generic or subgeneric rank is of little consequence. Furthermore, 

 it is contrary to accumulated knowledge of Nature's laws to expect 

 that any character should remain hard and fast and not grade, at 

 least in some species, toward other genera. However Dekayella 

 may stand with respect to Hetcrotrypa in the final revision of these 

 Bryozoa, wc think that Dekayia will stand as a genus, not in the 

 --(.use of Ulrich's definition of the genus in 1880/ but as defined in 

 our synopsis of the Heterotrypida on a preceding page. 



DEKAYELLA FOLIACEA new species 



(Plate VII, 10-12) 



The discovery of this flabellate species with its well-developed 

 large and small sets of acanthopores caused us to emend the generic 

 diagnosis so as to include frondescent species. Dekayella foliacea 

 grows into erect fronds of varying width and from 5 to 10 mm. in 

 tbickness. Externally the zooecia are angular, an average of 8 in 2 

 mm., the mesopores few, and both sets of acanthopores usually well 

 developed. 



Diaphragms are remote in the axial region, indeed are generally 

 wanting, but the peripheral zone is closely tabulated, 2 to 3 dia- 

 phragms being found in a distance equaling the diameter of a zooe- 

 cium. Mesopores are few, although the number is somewhat varia- 

 ble. The larger set of acanthopores is usually well developed, but 

 sometimes, especially in very old • conditions, the smaller set is 

 obsolete. 



The flabellate growth, rather few mesopores, and the double set of 

 acanthopores form a combination that is readily distinguished from 

 other Heterotrypidce. The flabellate form of the zoarium alone 

 suffices in separating it from congeneric species. 



Occurrence. — Lexington limestone of the Trenton, Lexington, 

 Kentucky. 



Cat. Xo. 43,187, U. S. X. M. 



Genus Leptotrypa Idrich 

 The genus Leptotrypa as defined by Ulrich in 1890 2 and 1893 3 

 proved to be quite a heterogeneous assemblage of species and an 

 unwarranted extension of the original diagnosis. In the first place, 



1 . liner. Pal. Bryozoa. 



2 Geol. Surv. Illinois, viii, p. yj~. 



3 Geol. Minnesota, in. p. 316. 



