132 ADDENDA AND CORRIGENDA. 



Polyzoariiim pedunculate, springing on a slender peduncle from the centre of an 

 orbicular, incrusting, discoid expansion. Cells oval or hexagonal, immersed ; surface uneven, 

 sparsely punctured. Orifice orbicular, notched below. Usually a small avicularium with 

 an acute mandible pointing upwards, on one side, close to and below the orifice. 



Habitat. — C. Crag, 8. Wood,, on shell. 



This is a very curious form, and for some time it was uncertain where to place 

 it. The only specimens met with are very imperfect, and present the aspect of several 

 short, broken stumps, arising in close contiguity from the centre of circular expansions, 

 firmly adnate to the surface of a shell. What the form of the perfect growth may be it is 

 at present impossible to say. In most cases the cells have become completely solidified, 

 or filled up by earthy matter, so that all vestige of the orifice, and nearly so of the 

 internal cavity, is absent. Owing to this circumstance, the surface of the broken 

 peduncle presents a curious appearance. This portion of the polyzoary seems to be made 

 up of solid conical prisms, at the apex of which may sometimes be observed all that 

 remains of the cavity of the cell, but in nearly all cases a transverse septum, separating 

 the prisms on the two sides of the peduncle, may be noticed, as in others of the branched 

 Escharas. The only species of Eschara with which this can be supposed to have any 

 connexion is E. incisa, but at present no sufficient ground exists for their being 

 associated. 



2. Lepralia edwardsiana (p. 44). 



When the above appellation was given to this species, I had overlooked the circum- 

 stance that M. D'Orbigny had given it, in 1839, to a species oi Lepralia {Escharina) 

 from the Coast of Patagonia.^ I propose, therefore, to term the Crag fossil L. milneana, 

 which will equally recal the name of the eminent naturalist and physiologist to whom we 

 are so deeply indebted for our knowledge of recent and fossil Polyzoa, as well as in all 

 other branches of zoological science. 



3. Elustra dubia {n. sp. ?) PI. I, fig. 3. 



Cells subpyriform, pointed at the suuuiiit. Many closed in front ? 



Habitat.— C Crag, S. Wood. 



Only one minute fragment of this curious growth has been met with in Mr. Searles 

 Wood's Collection. It has been assigned to the genus Flustra for want of any more 

 appropriate allocation — but it is extremely doubtful whether it will not, on further investi- 

 gation of larger specimens, be found to be erroneously placed there, and to represent a 

 distinct generic type. From its extreme fragility it would seem so far to have agreed 

 with Flus/ra as to have been more or less flexible when living. 



' ' Voy. d. I'Amer. merid.' (" Polypiers," p. 12, pi. v, figs. 1 — 4), 



