166 



MR. A. W. WATERS ON 



zooecia to an internode, with fresh branches given off from about 

 the second zooecium. 



Idmonea. 



Gregory, in his ' Catalogue of Cretaceous Bryozoa,' p. 150, 

 Would do away with Idmonea as we now understand it, and would 

 restrict it to " Idmoneidse with the zoarium adaate." He does 

 this taking I. triquetra, Lamx., as the type, which is stated by 

 Gregory to be aduate. Lamouroux's figures in 'Exposition 

 Methodique des Polypiers/ pi. 79. figs. 13 & 14, however, seem 

 to be drawn from an erect species ; and in his description of the 

 genus Idmonea Lamouroux says : " altera facie subcanaliculata," 

 showing that he had before him a free zoairum, and no doubt 

 most, if not all, workers have taken the description as referring 

 to an erect form. 



4. Idmonea atlantica, Forbes. (PI. 21. figs. 2, 3.) 

 Idmonea atlantica, Smitt, "Krit. Fort.," Ofvers. Vet.-Ak. Forh. 1866 

 pp. 399 & 434, pi. 4. figs. 5-9 ; Hincks, Brit. Mar. Polyzoa, p. 451 

 pi. 66. figs. 1-4; MacGillivray, Tert. Polyzoa Victoria, p. 122, pi. 16 

 fig. 17, pi. 17. fig. 8; Bidenkap, " Bry. Spitzbergen," Fauna Arctica 

 vol. i. p. 527 ; Waters, Resultats du Voyage du S. Y. ' Belgica ' : Bryozoa 

 p. 90, pi. 9. fig. 5. 



Por other synonyms Miss Jelly's Catalogue maybe consulted 

 but I feel considerable doubt as to whether the name has 

 always been correctly applied, and although we call it Forbes's 

 species there is uncertainty as to any determinations previous to 

 Smitt, and perhaps he would have done better by giving it a new 

 name. The branching is much less frequent than is shown in 

 Johnston's figure, and the dorsal surface is usually concave, 

 though it is sometimes convex as described by Johnston. The 

 •colonies grow to a considerable size, evidently two or three inches 

 in height. There are usually three zooecia in a series, which are 

 about 0'9 mm. to O'l mm. apart, and the closure occurs at a 

 short distance from the base of the erect portion. The bifurca- 

 tion is nearly always a broad distinct curve, as figured by Smitt ; 

 then the branches run nearly parallel. The aperture of the 

 zooecia is about 0*15 mm. wide. Unfortunately both Busk and 

 Hincks fail to give the magnification of their figures, so that no 

 comparison of size can be made. 



In the specimens from Franz-Josef Land the ovicell does not 



