50 THE CRAG POLYZOA. 



Habitat. Cor. Crag, on various shells, S. W. (Recent) Britain, ubique. 



Bearing a strong resemblance in most respects to large, coarse, overgrown specimens 

 of L. Peachii, the present species may usually be readily distinguished by the great con- 

 traction of the upper part of the cell, and the production of the peristome often into a 

 sort of funnel. 



19. L. BOWERBANKIANA (/?. */.) PI. VII, tig. 4. 



Cellulis subseriatis, ovatis, oblongis, antice convexis, umbonatis ; jimiorurn supcrncie 

 delicatule scrobiculatfi, seniorum, presertim ad latera, pnncturata. Orificio orbiculari, infra 

 sinuato, tribusque spinis margmalibus supra inunito. 



Cells subserial, ovate, oblong, convex in front ; surface of tlie young cells faintly scro 

 bicnlate, in the older punctate, especially at the sides ; orifice orbicular, with a sinus 

 below, and three marginal spines above ; a conical umbo close below the orifice. 



L. UNICORNIS, Johnson (MS.) 



Habitat. C. Crag, on Terebvaiula grandis, 8. 17. 



This species bears a resemblance to some states of the recent L. trispinosa, from which 

 it may be distinguished however: 1, by the invariable absence of any avicnlarium ; 2, by 

 the form of the orifice, whose border is always simply sinuatcd below, and never produced 

 in the spout-like fashion of that part in L. frisphiosa. 



20. L. LOBATA (. sp.) PI. VI, fig. 7 ; PI. XXII, fig. 4. 



Polyzoario medio depresso, marginem versus inerassato, in lobis inaequalibus irre- 

 gulariter diviso. Cellulis supra constrictis, infra latioribus, et ad basim alte immersis ; 

 superficie glabra. Orificio elevato, suborbiculari, labio inferiori, aviculario parvo, centrali, 

 armato ; spinis marginalibus duabus subinde connatis utrinque munito. 



Polyzoarium depressed in the centre, thick and raised towards the margin, and partially 

 divided into elevated lobes ; cells contracted above, wider and deeply immersed at the base, 

 surface smooth ; mouth raised, suborbicular, lower border with a small avicularium in 

 the middle ; two marginal spines sometimes connate, on each side. 



Habitat. C. Crag, on Pecten, S. W. 



The peculiar conformation of the polyzoarium in this species serves at once for its 

 distinction. In tolerably perfect specimens the patch is small and thick, almost like that 

 of an encrusting cellepore, cupped or depressed in the middle, and thicker towards the 

 border, where it is usually divided into a certain number of elevations or suberect lobes. 



