188 Prof. H. James-Clark on the Spongige ciliatse 



Lichen uncialis [Cladonia uneialis, Hffm.~\. Rocks and heaths. 



Lichen varius [Lecanora varia, AchJ], Old pales. 



Lichen venosus [Peltigera venosa, Hffm.']. Near Ludlow (Dr. 



Babington). 

 Lichen vernalis [Lecidea vernalis, Ac7i.']. "WaUs. 

 Lichen vespertilio [CoUema nigrescens, Ach.']. (See nigrescens.) 



XXVII. — 0)1 the Spongiee ciliatse as Infusoria flagellata; or 

 Observations on the Structure, Anwiality, and UelationsMp 

 of Leucosolenia botryoides, JBowerhank. Bj H. James- 

 Claek, A.B., B.S., Professor of Natural History in the 

 Agricultural College of Pennsylvania. 



[Continued from p. 142.] 



§ 4. Bicosoeca lacustris, n. sp. PI. V. figs. 33, 33^, 33^, 33«. 



This species lives in quiet streams and lakes, attached to 

 filamentous Algse, and is quite common, especially on old 

 specimens of Zygnema. It is 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 

 (r) 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 ^a^e//Mm [ji), and on the 

 opposite side in a long incmwed li^) {Ip). 



The longitudinal furrow (r'), which is so conspicuous in B. 

 gracili'pes, is much narrower in this species, and not so deep ; 

 yet it holds exactly the same relations to the base of the fla- 

 gellum {fi) and the contractile ligament (r). 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'', r') 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 if). The latter is very slender and thread-like, and is 

 attached to the posterior end of the body on one side (see 

 fig. 33^, r) of its axial line, and has very much the appearance 

 of being a free continuation of a ligament in the furrow just 



