98 PLUMATELLA REPENS. 



1839. Plumatella campanulata. Gervais, Ann. Fran9. et Etrang. d'Anat., torn, iii, 



p. 131. 

 181.8. Phtmatella repens, second variation. Allman, Rep. Brit. Assoc, Trans, of 



Sect., p. 74. 



Iconography. — The only original figure of this variation is that of Rosel. 



Habitat.— In lakes and ponds, and in rivulets of moderate rapidity, attached to the 

 under surface of stones, and to the stems of aquatic plants, and under side of floating leaves, 

 avoiding the light. 



Localities.— BnVM; Generally distributed throughout England and Ireland, in some 

 places very abundant. In Scotland it occurs as far north as the Orkneys, whence I have 

 obtained specimens from Lieutenant Thomas, who collected them there in Bea Loch, Sanda ; 

 it is probably generally distributed through Scotland, having been met with there in 

 various localities by Dr. Fleming, Sir J. G. Dalyell, and myself. 



Foreign : Among continental localities, may be mentioned Lake of Lucerne, Lago di 

 Como, in both of which I obtained it during the summer of 1854 ; the Alpine lakes, Lac 

 Seculejo and Lac d'Aul in the Pyrenees, where I obtained it in the autumn of 1856; in the 

 former at an elevation of 4590 feet, and in the latter at about 6500 feet above the level of the 

 sea. It has been met with also in other parts of France and Italy, as well as in Belgium, 

 Germany, Prussia, Sweden, and Denmark, as recorded by Raspail, Van Beneden, Dumortier, 

 Rosel, Schaffer, Linnaeus, Miiller, Risso, and other continental naturalists. 



If Plumatella repens be identical with P. nitida, Leidy, (see below, p. 109,) we will 

 have then, on the authority of Dr. Leidy, an American locality (Pennsylvania) to add to 



the above. 



Plumatella repetis is a very elegant Polyzoon; the orifices for the egress of the polypides 

 terminate in short, free, tubular ramuli formed by the continuation of the cells, and placed 

 at intervals along the main branches, generally singly, but sometimes in groups of two, three, 

 or even more. The quantity of earthy matter deposited in the ectocyst is small, and this 

 tunic is generally more pellucid than we find it in most other species of the genus ; it varies, 

 however, in this respect, according to age and locality of growth, and is for the most part of a 

 brown, or tawny colour, except in the immediate vicinity of the orifices, where it always 

 becomes colourless and transparent ; through this transparent portion, the endocyst is visible, 

 and may be here generally seen, dotted with minute, opaque, white spots. 



We should be careful not to lose sight of the existence of two distinct variations in this 

 species, since a want of the proper recognition of their true significance has given rise, as we 

 have already seen, to a mass of confusion in the synonyms of P. repens, such as, perhaps, can 

 scarcely be paralleled in the literature of Zoology. In the first of these variations, (var. a,) 

 which must be viewed as the normal and typical condition, the animal may be seen attaching 

 itself to flat surfaces, as the under side of stones, and of the floating leaves of the water lily 

 and other aquatic plants. In this condition it is closely adherent throughout its entire length 

 to the surface on which it is developed, and forms elegant dendritic, or confervoid growths, 

 radiating from a common centre. In the second, (var. ^,) it will be found fixed to surfaces of 



