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Cincinnati Society of Natural History. 



ization, the basal membrane of the incrusting bryozoan is brought to 

 view, and sometimes beautifully preserved. Wlien moisture is applied 

 to these specimens the tubes show through the epithecal membrane as 

 small oblong patches, frequently with a length equaling five or six 

 times the breadth or true diameter of the tubes. Although the basal 

 membrane of certain species of Ceramopora present a very similar 

 appearance, it does not follow that the one is developed out of the 

 other. It might as well be urged that species of Ptilodictya, in their 

 primitive stages, were Ceramopora}, since we find on an examination 

 of the median membrane, or germinal plate, that an essentially iden- 

 tical structure is present. The incrusting and double-leaved species 

 of the Monticuliporidai, species of Ceramopora, Lichenopora, Beren- 

 icea, Crescis, and other genera of the Bryozoa, show at the margin of 

 the colony an extension of the germinal plate (epitheca), which is 

 always occupied by the young and undeveloped cellules. That this 

 character, upon which Dr. Lindstrom based his assertion, that Monti- 

 culipora is developed from Ceramopora, is of much importance in the 

 consideration of the zoological position of the Monticuliporidai, can 

 not be doubted. So far as the writer is aware, no analagous feature is 

 present in any of the undoubted Cwlenterata: and as it is invariably 

 present in so man}' indubitable genera of the Bryozoa, we must regard 

 the character as furnishing one of the strongest arguments in favor of 

 uniting the Monticuliporidai with the Biyozoa. The typical species 

 of Ceramopora (e. g. C. imbricata, Hall, etc.), are quite distinct from 

 all of the Monticuliporidai, but through C. ohioensis, Nicholson, and 

 C. tvhitei, James, and the species of Crepipora, Ulrich, the limits of 

 the family Ceramoporidce are laid quite close to those of certain genera 

 of the Monticuliporidai. In Ceramopora whitei, James, the cells are 

 tubular, and occasionally a few diaphragms are present; the cell aper- 

 tures are veiy little oblique, and, in consequence, the characteristic 

 feature of the family (the overhanging lip), is but slightly developed. 

 On the whole, the species affords a zoarium not very unlike that of 

 species of Spatiopora (S. crustulata, James, and S. lineata, Ulrich). 

 In the Crepiporce the cell-apertures are direct, and the lip is scarcely 

 developed at all; diaphragms are present, as well as spiniform tubuli; 

 very distinct "maculae'' are also developed, which, in all respects, are 

 like those of Atactopora maculata, Ulrich, and with the exception of 

 one generic character (i. e. the two converging lamellae, which are 

 situated one on each side of one of the angles of a tube), the species 

 of Crepipora possess zoaria which would pass very well for those of 



