188 Prof. H. James-Clark on the Spongie ciliate. 
Inchen uncialis [Cladonia uncialis, Hff'm.]. Rocks and heaths. 
Tachen varius [Lecanora varia, Ach.}|. Old pales. . 
Lichen venosus [Peltigera venosa, Hffm.]. Near Ludlow (Dr. 
Babington),. 
Inchen vernalis [Lecidea vernalis, Ach.]. Walls. 
Lichen vespertilio [Collema nigrescens, Ach.]. (See nigrescens.) 
XXVII.—On the Spongie ciliate as Infusoria flagellata; or 
Observations on the Structure, Animality, and Relationship 
of Leucosolenia botryoides, Bowerbank. By H. JAMEs- 
LARK, A.B., B.S., Professor of Natural History in the 
Agricultural College of Pennsylvania. 
[Continued from p. 142. ] 
§ 4. Bicoseca lacustris, n.sp. Pl. V. figs. 33, 334, 33>, 33°. 
This species lives in quiet streams and lakes, attached to 
filamentous Alge, and is quite common, especially on old 
specimens of Zygnema. It 1s tinged throughout with a yel- 
lowish colour, which seems to add a good deal to the difficulty 
of distinguishing its various parts. When protruded (fig. 33), 
It occupies the anterior half of the calyx (c) and projects a 
little beyond its edge, and consequently its retractor ligament 
(7) stretches over the whole posterior half of the dormitory. 
The shape is rather elliptical than elongate-oval ; but it varies 
more or less between these two forms, and seems to have the 
latter shape in the largest individuals. Posteriorly the body is 
rounded ; but its broadest region is about the middle, and from 
thence it tapers considerably to a truncate front, and ends on 
one side in a laterally projecting flagellum (fl), and on the 
opposite side in a long incurved lip (/p). : 
The longitudinal furrow (r!), which is so conspicuous in B. 
gracilipes, is much narrower in this species, and not so ar 
et it holds exactly the same relations to the base of the fla- 
gellum (7) and the contractile ligament (7). After a number 
of observations upon the frequent and sudden retraction of the 
body to the bottom of its calyx, during which in every instance 
that side along which the furrow (fig. 33°, 7!) runs was con- 
tracted much more than the opposite one, I feel quite confident 
that this sulcus is the seat of a highly contractile band, and 
moreover that it is continuous with the posterior retractor liga- 
“ment (r). The latter is very slender and thread-like, and is 
attached to the posterior end of the body on one side (see 
fig. 334, r) of its axial line, and has very much the appearance 
of being a free continuation of a ligament in the furrow just 
