Polyzon of the St. Liivrence. 215 



treal Museum, who have placed in my hands for examination 

 their collection of the Hydroida and Polyzoa of the St. Law- 

 rence. Circumstances have hitherto prevented me from 

 making much progress with the work, and I have to apolo- 

 gize for a delay which I did not anticipate and much regret. 

 As it would only lead to further delay to defer publication 

 until the whole of the material has been examined, I propose 

 to commence at once with studies of new forms as they occur, 

 and such as from any cause seem to require further illus- 

 tration, reserving the complete systematic list of species and 

 general conclusions for the close of the Report. 



Subclass Cheilostomata. 

 Family BicellariidaB. 



CORYNOPORELLA, n. gen. 



Generic character. Stems slender, consisting of cells dis- 

 posed in single series and facing one way, dichotomously 

 branched ; zooecia more or less clavate, each cell originating 

 from the dorsal surface of the one beneath it, immediately 

 below the summit, elongate, the inferior portion (from a little 

 below the aperture) much attenuated, tubular ; aperture at 

 the top of the cell, occupying a small proportion of its length. 

 Avicularia articulated, attached to the side of the aperture. 



Corynoporella tenuis^ n. sp. (PI. XV. figs. 1.) 



Zoarhim minute, transparent ; stems slender, bifurcating at 

 intervals. Zooecia subclavate, much elongated, slightly ex- 

 panded towards the upper extremity which is rounded, the 

 inferior portion very slender ; aperture extending down 

 rather less than a third of the length of the cell, occupying 

 its entire width above, and tapering off to a rounded point 

 below, margin thin and destitute of spines, upper wall 

 wholly membranous ; orifice arched above, straight below ; on 

 the margin at one side less than halfway down the cell a 

 rather large articulated avicularium, the dorsal surface sloping 

 abruptly upwards from the peduncle (which is short) and very 

 protuberant, the top flattish, terminating in a long beak-like 

 extremity, not abruptly bent ; surface smooth, the whole 

 structure (viewed laterally) somewhat wedge-shaped. Fibrils 

 given off from the dorsal surface of the cell, a little below the 

 summit towards one side. Ocecium (?). 



Hah. Forming small tufts attached to other Polyzoa. 



15* 



