PLUMATELLA VESICULARIS. W)l 



Specific character. — Coencecium adherent, creeping, irregularly branched, branches com- 

 posed of a series of large conical cells, tapering towards the orifice, destitute of furrow ; 

 the upper portion of the cell almost colourless and freckled with minute, opaque, white spots. 

 Tentacula about sixty ; calyx distinctly festooned. Statoblasts broad. 



Synonym. — Plumatella punctata. Hancock, Ann. Nat. Hist.^ 2d series, vol. v, p. 200, pi. v, figs. 

 6, 7, and pi. iii, fig. 1. 



Iconoc/rajihi/. — Original figures of Hancock. 



Habitat. — Adhering to the under side of stones in lakes. 



Locality. — Bromley and Crag Loughs, Northumberland. Hancock. 



The following is Mr. Hancock's description of this species : 



" Polypidom adhering throughout, coriaceous, pellucid, of a pale, watery, green colour, 

 irregularly but not much branched, seldom extending more than half an inch ; branches com- 

 posed of a series of large, conical cells, tapering upwards towards the aperture, sometimes 

 considerably and rather suddenly dilated at the base, resembling in form some of the 

 Ascidians ; the upper portion of the cell almost colourless, and freckled with minute, opaque, 

 white spots, most crowded towards the orifice. Tentacles white, not more than sixty 

 in number ; membrane at their origin rather wide, scalloped, the points of the scallop 

 extending for some distance up the back of the tentacles in the form of broadish laminae 

 arched outwards. CEsophagus and stomach appearing through the transparent walls of the 

 cell of a pale yellow colour. Egg perfectly black, large, broad, and oval. 



" Upwards of a dozen specimens of this fine species occurred in Bromley Lough, 

 adhering to the under side of stones ; it was likewise taken in Crag Lough. None of the 

 individuals much exceeded in size that represented in the figure, nor did they vary in any 

 remarkable manner either in form or colour. It is not, however, without hesitation that 

 I ventured to characterise this as a new species, as Professor AUman informs me that it 

 may perhaps turn out to be P. repens ; but that form is stated to be large and of luxuriant 

 growth, and to have the polypidom tubular with the cells dilated at the orifice — characters 

 which do not at all agree with P. jmnctata. Indeed it can scarcely be considered a true 

 Plumatella:' 



I have never seen a specimen of P. punctata, but having read Mr. Hancock's detailed 

 description I now agree with him in considering the species as a good one. Still, however, 

 it comes very near to P. repens, closely resembling the young state of this species before the 

 coenoecium has acquired the more decidedly tubular condition of the adult. 



4. Plumatella vesicularis, Leidy. 



Specific character. — " Coenoecium radiating and branched, attached, colourless, and trans- 

 parent ; each segment slightly dilated and much broader than the protuberant orifice of exit. 



