a General History of the Marine Polyzoa. 383 



orifice, arched above, the sides inclining slightly inwards, the 

 lower margin (which is somewhat curved outwards) bearing 

 a round avicularium ; within it three denticles, the central 

 one hammer-shaped, the two lateral acute ; immediately below 

 it a tall and veiy stout rostrum, with a smaller one on each 

 side of it, the three stretching across the cell; at the 

 top of the orifice usually two or three similar processes of 

 smaller size, sometimes two spines on the upper margin. 

 Ooecia (?) . 



Loc. Australia {Miss Jelly). 



In this curious species the cells are often separated from 

 one another, an open space or groove lying between the 

 margins. 



Mucronella, Hincks. 



Mucronella (?) tubulosa, n. sp. (PI. XVII. fig. 7.) 



Zooecia large, irregularly arranged, suberect; surface white, 

 smooth, and glossy, very convex and subcarinate in front ; 

 orifice suborbicular, depressed ; peristome very much raised on 

 the sides and in front, so as to form with the wall of the 

 neighbouring cells a wide funnel-shaped shaft, in which the 

 mouth is quite concealed ; peristome carried up in front into 

 a massive central mucro ; at the base of it a large lingui- 

 form avicularium, much raised ; mandible directed downwards. 

 Ooecium rounded above, somewhat compressed and flattened 

 towards the orifice, smooth or very minutely roughened, 

 placed at some distance above the mouth, towards the upper 

 part of the oral shaft. 



Loc. Australia {Miss Jelly). 



This is a remarkable form, distinguished especially by the 

 position of the ovicell, and the ample funnel-shaped shaft in 

 which the mouth is immersed. The arrangement of the 

 zooecia is also peculiar. I have only had the opportunity of 

 examining a small fragment and can hardly determine with 

 certainty its generic place. For the present it may be referred 

 to Mucronella, with which it has apparent affinity. 



EXPLANATION OF THE PLATES. 

 Plate XVI. 



Fig. 1. Steganoporella Rozieri, Audouin, form indica. la. Ooecium. 



Fig. 2. Steganoporella Rozieri, Audouin, f orm falcifera. 



Fig. 3. Steganoporella Rozieri, Audouin, form gothiea, Busk. 



Fig. 4. Steganoporella elongata, n. sp. 



Fig. 5. Steganoporella Jervoisii, n. sp. 5 a. Avicularium. 



Fig. 6. Micropora coriaeea, Esper, var. 



Fig. 7. Membranipora tenella, n. sp. 



Fig. 8. Memhranipora Flemingii, Busk, unarmed variety. 



