Polyzoa of the St. Lawrence. 227 



posed of a membranaceous material. The muscular cylinder is 

 tall and stout, decidedly conical above, and of a whitish 

 colour. The length of the fleshy stalk immediately supporting 

 the polypide and by which it is attached to the pedicel is a 

 distinctive character. It is dilated below the body of the 

 polypide, which is large and pretty regular in shape. The 

 pedicels are developed in great numbers on the stolon ; at the 

 point where each originates opposite branches are given off. 

 Loc. St. Lawrence. 



EXPLANATION OF THE PLATES. 



Plate XIV. 



JFiff. 1. Escharoides Sarsii, Smitt. Adult zocecia from the older portion 



of a colony. 1 a. Zooecia in the earlier stages of development. 



1 b. Zocecia, showing the development of the oral avicularium. 



1 c. Early stages in the growth of the avicularium. 

 JFiff. 2. Smittia Landsborovii, Johnston (sp. ), iovva. liorifera, Smitt. 

 Fig. 3. Smittia Landsborovii, Johnston, normal. 

 Fig. 4. Porella proboscidea, n. sp. [This figure and also 5 and 5 a are 



less hitjlily magnified than the rest of the Plate.] A a, A. single 



zooecium. 

 Fig. 5. Membraniporella crassicosta, n. sp, 5 a. Immature zooecia, 

 Fig.Q. Porella Skenei, Ellis & Sol,, form plana, u, var, 6 a, Ocecium, 



b. Marginal zooecium, showing tlie primary orifice and early 



stage of the avicularian chamber. G c, Zoarium, nat. size. 



Plate XV. 



Fig. 1. Corynoporella tenuis, n, gen, and sp, A zooecium, drawn to the 

 usual scale, 1 a. Portion of the zoarium, less highly, magnified, 

 showing the dorsal surface, the mode in which the cells are 

 connected, and the position of the fibrils. 



Fig. 2. Barentsia major, n, sp, A single pedicel and polypide, 2 a. 

 Ditto, showing the mobility secured to the polypide by the 

 fleshy stalk by which it is attached to the pedicel, 2 6. A pedi- 

 cel on which a new polypide is in course of development. 



Fig. 3. Mucronella prcelucida, Hincks, 



Fig. 4. Membranipora cgmbiformis, Hincks. 4 a. Marginal zooecium. 



Fig. 5. Porella elegantula, D'Orbiguy, var. rostrata. 5 a. Young zooecium, 

 showing an early stage in the development of the avicularium. 

 5 h. The avicularian mandible. 



Fig. 6, Cellularia Peachii, Busk, showing the cusp on the median cell at 

 a bifurcation. 



