354 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



later the body became rounded, the transverse furrow moved in a 

 posterior direction, and the membrane acquired plates, whilst the lon- 

 gitudinal furrow-apparatus remained entire (^Protoperidinium). From 

 this point began the develoj^ment in two directions, since on one 

 side the ridges {Peridinium, Protoceratium, Ceratium) and on the 

 other the horn-like processes of the longitudinal furrow (Diplopsaria, 

 Glenodinium) were reduced, and finally the plates coalesced. The 

 highest division is represented by the Gymnodinida in which sub- 

 family the membrane is quite abolished, and numerous differentia- 

 tions of the protoplasm developed. Finally, springing from these, 

 are forms in which the flagellum is reduced, but in which a cytostom 

 and cytopyge are differentiated in order to give origin to the Peri- 

 tricha, the oldest ciliated Infusoria (Mesodinium). 



L. Maggi* establishes the occurrence of Ceratium f urea Ehrenberg, 

 hitherto almost exclusively known as marine, in certain lakes of Upper 

 Italy (Lago di Candia, near Ivrea, and Lago di Annone, in Brianza) ; 

 at the same time he devotes much attention to the synonymy of this 

 species and to the history of the investigations into the phosphorescent 

 powers of the Ceratia. Like Claparede and Lachmann, he regards 

 Peridinium lineatum as identical with Ceratium furca. The form was 

 not observed alive, but only the remains of its tests ; among these 

 occurred in the Lago di Candia, a considerable number somewhat 

 differently shaped, which the author thinks right to constitute a special 

 variety, under the name lacustris. 



The same writer f gives a list of all the Cilio-flagellata known to 

 him through literature or by original observation, adding the syn- 

 onyms and habitats of each form. He retains the following five 

 genera: — Ceratium (with seventeen species, two of which are fossil), 

 Peridinium (with thirty species, all recent, two fossil ones also occur), 

 Dinophysis (seven species), Amphidinium (one species) and Prorocentrum 

 (one species). He believes that Claparede and Lachmann have gone 

 too far in their reduction of the number of the species, and have 

 allowed themselves to be guided by reasons which will not bear in- 

 vestigation. He endeavours to show here, as in another place, that 

 the Cilio-flagellata were originally derived from the sea, in which even 

 at the present time they attain so great an importance, and have only 

 later extended into fresh water. By this means the circumstance is 

 explained of their inhabiting more particularly the larger fresh-water 

 lakes, for in these are found conditions resembling to a certain extent 

 those of the sea. On this view Prof. O. ButschliJ remarks that the author 

 has not paid attention to Stein's writings on the Cilio-flagellata, or 

 he would have seen that Stein distinguishes three additional genera, 

 Gymnodinium, Hemidinium, and Glenodinium, but is inclined to remove 

 the genus Prorocentrum from the group. 



L. Maggi § further arranges together all the Cilio-flagellata known 



* Bollet. Scientif., i. (1880) pp. 125-8. Cf. Zool. Jahresber. Neapel for 

 1880, i. p. 167. 



t Op, cit., ii. (1880) pp. 7-16. Cf. torn, cit., p. 167. 



: Tom. cit., p. 167. 



§ Kendic. R. Istit. Lombard, xiii. (1880) p. 20. Cf. Zool. Jahresber. Neapel, 

 torn, cit., pp. 167-8. 



