NORTHUMBERLAND AND DURHAM. 145 



This beautiful little species is smaller than the two last, and 

 resembles a good deal some specimens of Lepralia nitida. It is 

 probable, therefore, that Dr. Johnston had this form in view 

 when he expressed a doubt of the distinctness of M. lineata from 

 that Lepralia. The spines in this are a little flattened at the 

 sides and glistening, like the ribs of L. nitida; but they, as well 

 as the cells, are smaller than in that species, and want the mid- 

 rib, that unites the whole into regular cell-walls. The lower 

 spines lie close to the aperture, and converge to a point near the 

 centre of the cell. It is distinguished from M. lineata^ as 

 restricted above, by the smaller size and linear arrangement of 

 the cells, by the stouter, flatter, and more recumbent spines, and 

 by the smaller and more cylindrical ovicapsules. 



The only specimens I have procured on this coast are from 

 deep water, but Mr. Barlee has sent me a specimen beautifully 

 developed on a small littoral sea-weed. 



6. M. Flemingii, Bush PL X., fig. 4. 



Cells ovate, broad below, with a granulated margin, partially 

 filled in by a corneous or subcalcareous expansion, leav- 

 ing a triangular aperture; spines long, 3 on each side, 

 confined to the upper half of the cell. Ovicapsule 

 smallish, globular, slightly frosted, generally with an 

 arched rib near the top. Avicularia numerous, dispersed, 

 usually one on each side of the ovicapsule, sometimes one 

 above it, and frequently one below the aperture of the cell . 

 Membranipora membranacea, Johns. Brit. Zooph., 



328 (part). 

 Membranipora Flemingii, Busk, Catal., 58, t. Ixi., f. 2, 

 and t. Ixxxiv., f. 4 — 6. 

 On shells, stones, Flustroe, &c., from between tide-marks to 

 deep water; common. 

 When developed in a sheltered situation, this species appears 

 bristling with long spines, and is then readily recognised ; but in 

 exposed situations, and more especially in deep water, the spines 

 are frequently wanting. In this condition it may, however, be 

 known by the expansion which partially fill in the cells, hi 



