MEMBRANIPORID^.. 41 



3. L. PUNCTURATA, S. Wood. ?\. VI, fig. 2. 



Celliilis ovoideis, convexis, utririque 5 — G sulcis porosis ornatis ; orificio suborbiculari, 

 labio inferiori incrassato, elevate, supra spina marginali media unica et utrinque avicu- 

 lario armato ; ovicellula depressa, rotundata, antice punctis 3 signata. 



Cells ovoid, convex ; 5—6 sulci on each side ; punctures along the sulci ; orifice sub- 

 orbicular, lower margin thickened, prominent ; a single median marginal spine above ; an 

 avicularium on each side of the mouth ; ovicell depressed, rounded, with three punctures 

 in front. 



1j. punctuuata (pars), S. W., Ann. Nat. Hist., xiii, p. 18. 



Habitat. — Red Crag, S. W., on the inside of Cytherea rudis and (?) Cardium mdgare. 



The only species with which the present can be confounded is L. punctata, a species 

 very abundant in the Coralline, but also occurring in the Red Crag, to which L. jmnctu- 

 rata seems to be confined. Both species have the front of the cell punctured in a some- 

 what similar manner, and both have an avicularium on each side of the orifice ; so that 

 in general aspect, on a superficial inspection, they might be very readily confounded. 

 The differences between them, however, seem amply sufficient to separate them. 



1. The ovicell in L. punctata is pyramidal, carinate in front and not punctured, and 

 often has an avicularium on the summit ; whilst in L. pu7icturata the ovicell is depressed 

 and rounded, with three distinct puncta on its anterior surface, which is either quite 

 smooth, or raised into a short umbo. 



2. The lines of punctures in L. punctata are, for the most part, continued across the 

 cell uninterruptedly, showing but little disposition to radiate from the centre ; whilst in 

 L. puncturata the fines of punctures are, in almost every instance, placed in grooves dis- 

 tinctly radiating from a central line, across which the punctures are not continued, as in 

 L. annulata. 



3. The cells in L. punctata are always deeply immersed, and usually disposed in linear 

 series, whilst in L. puncturata they are very convex in front, distinct from their neigh- 

 bours, and disposed quincunically. 



4. The single median spine on the upper margin of the mouth is a further distin- 

 guishing characteristic of L. jmncturata. 



Finding several specimens marked L. puncturata in Mr. S. Wood's collection, I have 

 retained his appellation for this form, although it would seem he did not himself distin- 

 guish it from L. punctata. 



