314 Rev. T. Hincks on the 



and is set straight in the line of the cells. [Compare PI. IX. 

 figs. 1 «, 2 a.] 



I have only had the opportunity of examining small pieces 

 of F. tenella and am therefore unable to give any account of 

 its general hahit of growth * . 



Flustra pusilla, n. sp. (PI. IX. fig. 9.) 



Zooecia in one layer, small, rounded above, the upper por- 

 tion wide, narrowing off below, truncate at the base (occa- 

 sionally running to a point), margin very thin, smooth, no 

 spines. AvicuJaria distributed amongst the cells, numerous, 

 situated on a small quadrate area, at the bottom of a cell, 

 usually placed transversely, very regularly oval, slightly 

 elevated at one extremity ; mandible short, rounded at the 

 top. Ooecia{?). 



Dorsal surface of the zooecia convex, smooth, sutures well- 

 marked. 



The only specimen which has occurred consists of a very 

 small elongate segment attached to the stem of a seaweed. 



F. pusilla bears a close general resemblance to F. mem- 

 h-anaceo-t7-uncata, Smitt, a common northern species ; but 

 the cells of the latter are much larger and more elongate than 

 those of the present form, which approach the ovate type, 

 whilst there is a striking difference between the avicularia 

 (PI. IX. fig. 9, compared wnth fig. 10). The specimen ex- 

 amined consists of a single lamina. 



Group b. 

 Membranipora. 

 Memhranipora tenuirostn's, Hincks. 

 Range, Madeira ; Naples ; Queen Charlotte Islands. 



[Section Amphiblestrum.] 



Memhranipora patellaria^ Moll, form multijunctaj 

 Waters. 



Hah. On shell. 



Range. Mediterranean (normal), Moll] form multijunctaj 

 Naples ; Victoria. 



* The pariigraph respecting Flustra securifro7is in tlie early part of 

 the paper must be cancelled, with the exception of the portion relating to 

 the ocecium, which must be referred to the present species. 



