308 POLYZOA HTFUNDIBULATA. 





by Mr. Hassall. The crust is extensive, closely adherent, varnished, 

 whitish or straw-yellow, with unformed cells on the edge ; the cells 

 rather large, well-defined, ovato-ventricose, rising anteriorly, with 

 thin semi-vitreous parietes, and the space at the base between the 

 cells somewhat punctured or areolated. The aperture is large, sub- 

 circular, and oblique. In the specimens of Mr. Thompson before me, 

 the mucro on the proximal margin is rather obtuse but not " bifur- 

 cate," nor emarginate, as it is represented by Mr. Hassall ; and the 

 two or, rarely, three spines on the distal side are perfect only in a 

 very few cells, but vestiges of them are observable on most of them. 



1 0. L. LINEARIS, " cells much depressed, radiating in lines 

 from a centre, and increasing in size towards the edge of the 

 crust, upper part rounded ; aperture contracted, circular, with 

 a minute spout-like elongation below ; teeth either three or four, 

 surrounding the upper half of the aperture : on either side of 

 the small spout-like elongation referred to, a short Hunt process 

 is visible.' 1 '' A. H. Hassall. 



PLATE LIV. FIG. 11. 

 Lepralia linearis, Hassall in Ann. and Mag. Nat. Hist. vii. 368. pi. 9. fig. 8. 



Hob. " On stones east of Kingstown harbour, and at the Giant's 

 Causeway : not common," A . H. If assail. 



The only specimen I have seen forms a thin, white, sub-circular 

 crust on the inner surface of a valve of Pecten opercularis. It is 

 marked with lines visible to the naked eye, produced by the septa 

 between the rows of cells, the apertures of which are also distin- 

 guishable. The cells are horizontal, coalescent, oblong, divided by 

 distinct septa, slightly dilated towards the aperture, which is small, 

 circular, even, with a neat sinus on the proximal margin, and a hol- 

 low tubercle on each side projecting like a shoulder. The walls are 

 vitreous and obsoletely granulous. Ovarian capsules small, globose, 

 granulated or punctured, with a large perforation on the posterior 

 side. 



The species is nearly allied to Lep. auriculata, and belongs to 

 the same natural section as the Lep. trispinosa, the edge of the crust 

 being unfinished and marked with the divergent lines that mark the 

 boundaries of the nascent cells. My specimen is a good one, yet not 

 a single cell possesses any marginal spines on the aperture ; another 

 proof of the imperfect value of them in affording a specific character. 



