FLUSTRA CAHBASEA. 123 



consists of foliaceons fronds^ which divide near the base 

 into segments ; these again subdivide^ and at the top are 

 cut into shallow blunt lobes. The habit is neat and 

 compact. When dry the zoarium has a varnished appear- 

 ance. There is nothing very distinctive in the character 

 of the ocecium ; it is globose in form, moderately shallow, 

 with a lai-ge aperture, completely filled in by a membranous 

 covering, the arch of which alone rises above the surface 

 of the zoarium. The immediate cause of the immersion 

 of the ovicell is at once apparent in the case of cells from 

 which the front wall has disappeared. It is then evident 

 that the top wall of the zocecium, to ivhich the ovicell is 

 attached, is considerably lower than the side walls, which 

 support the roofing. The consequence is, that when fully 

 developed the ovicell is still below the surface, inclosed by 

 the sides of the cell above it, and concealed by its mem- 

 branous covering. 



This is one of the many forms which we owe to Mr. 

 Barlee's assiduous labours as a dredger. 



b. Zooecia in a single layer. 

 Flustra carbasea, Ellis and Solander. 



Plate XYI. figs. 4, 4 a, and Plate XIV. fig. 1. 



Flustra carbasea (Lawn Sea-mat), EU. ^ Sol. Zooph. xiv. pi. iii. figs. 6, 7: 

 Lamk. An. s. Vert. ed. 2, ii. 221 : Flem. B. A. 535 : Grant, 

 Ed. N. P. Journ. iii. Ill: Dalyell, Eem. An. Scotl. ii. 3, 

 pis. i. & ii. : Johnst. B. Z. ed. 2, 345, pi. Lsiii. figs, 1, 2: 

 Kircheiqoaitcr, Bericht. ii. d. Untersuchungs-Fahrt d. ' Pom- 

 merania,' 177, 178. 



Carbasea papyeacea, Gray, Cat. Ead. B. M. 103. 



Carbasea papyrea, Bvsk, B.M. Cat. i. 50, pi. xlix. figs. 1, 2, 3: Alder, 

 North. & Durh. Cat. 61. 



