78 SUMMARY OF CURRENT RESEARCHES RELATING TO 



aboral or posterior liorn (anterior of Stein) is inserted by a truncated 

 extremity at the left-hand margin of the ventral depression of the 

 succeeding individual, just at the point of termination of the transverse 

 furrow. The individuals in chains were motionless, with neither 

 flagellum nor cilia. 



This arrangement, and especially the apparent anterior evolution, 

 would seem to approximate the Ceratina to the Diatoms and Desmids, 

 while other peculiarities appear to indicate a relationship between 

 these creatures and the Nodiliicce closer than that accepted by Stein, 

 who places his groujis Scytomonadina between the latter and the 

 Peridinina. Some large Ceratia allied to C. diver gens, and about 

 0*160 mm. in length, show remarkable characters. The protoplasm, pro- 

 tected by the carajDace, is slightly rose-coloured, with a large spherical 

 nucleus and some drops of oily appearance and of a bright chamois- 

 colour ; the creature is asymmetrical, and as if twisted upon its axis ; 

 the extremity (truncated as usual) of the aboral horn appears excavated 

 into a groove ; and on the right-hand side of the ventral depression 

 there is a strong projection in the form of a lamp (Claparede and 

 Lachmann, Stein). All these characters occur in a striking manner 

 in the Noctilucce, especially at the moment of an ascent of these 

 creatures to the surface of the sea : — flagellum (Huxley, Eobin, Stein) ; 

 envelope hyaline, resistant, sometimes distinctly reticulated ; rosy 

 coloration of the protoplasm, with a nucleus and oily drops of the 

 same dimensions and the same colour ; well-marked asymmetry in the 

 basal piece of the tentacle and lip projecting on the right side (Huxley, 

 Eobin). 



The analogy becomes still more manifest if, instead of spherical 

 floating Noctilucce, we take the forms which have already puzzled 

 Busch, and which are not found at the surface, but at the bottom of 

 the vessels in which the products of fishing have been collected. In 

 these the internal framework (formed, not by a style or bacillus, but 

 by two kinds of glumes) produces by its extremities, three processes 

 or horns — two in front, pointed, and more or less recurved, and a 

 third aboral, excavated into a groove. The size of these tricuspid 

 Noctilucce [Q- 1^0 mm.) scarcely exceeds that of the large Ceratia from 

 which they seem to have issued, to become subsequently swelled up 

 by accumulation of water in lacunae originally independent of their 

 protoplasm. In these Noctilucce there is often a prominent curved 

 projection, which seems to mark the contour of the ciliary circlet. Of 

 the formation of the tentacle the author can say nothing, and he 

 remarks that the suggested relationship is pui-ely hypothetical. 



New Thuricola.* — Dr. A. C. Stokes describes a new species of Kent's 

 recently established genus Thuricola (T. innixd) found on the leaflets 

 of Ceratophyllum. The lorica is sessile, transparent, sub-cylindrical, 

 four to five times as long as broad, truncate, and somewhat tapering 

 posteriorly, bearing at some distance from the orifice an internal 

 valve-like appendage as in T. (Vaginicola) valvata, and an opposite, 

 rigidly attached, but flexible, membranous organ projecting arcuately 



♦ Araer. Mon. Micr. Jouni., iii. (1882) pp. 182-3 (1 fig.). 



