CERATIUM 771 



forms of the cilio- flagellate group belong to the genus Ceratium (fig. 

 f)91), in which the cuirass extends itself into long horny appendages. 

 In the Ceratium tripos (I) there are three of these appendages ; two 

 of them curved, proceeding from the anterior portion of the cuirass, 

 and the third, which is straight or nearly so, from its posterior 

 portion. They are all more or less jagged or spiiious. In Ceratium 

 furca (2) the two anterior horns are prolonged straight forwards, 

 one of them being always longer than the other ; whilst the posterior 

 is prolonged straight backwards. >The anterior and posterior halves 

 of the cuirass are separated by a ciliated furrow, from one point of 

 which the flagellum arises ; and at the origin of this is a deep 



FIG. 591. 1, Ceratium tripos; 2, Ceratium furca. 



depression into which the flagellum may be completely and suddenly 

 withdrawn. The Author has found the Ceratium tripos extremely 

 abundant in Lamlash Bay, Arran, where it constitutes a principal 

 article of the food of the Antedons that inhabit its bottom. 1 



Ciliata. As it is in this tribe of animalcules that the action of 

 the organs termed cilia has the most important connection with 

 the vital functions, it seems desirable here to introduce a more 

 particular notice of them. They are always found in connection 

 with cells, of whose protoplasmic substance they may be considered 

 as extensions, endowed in a special degree with its characteristic 

 contractility. The form of the filaments is usually a little flattened, 



1 See Allman in Quart. Microsc. Journ. vol. iii. 1855, p. 24 ; H. James-Clark in 

 Ann. Nat. Hist. ser. iii. vol. xviii. 1866, p. 429 ; Bergh, Morphol. Jahrbuch. vii. 1881. 

 p. 177, and Vanhoffen, Zool. Anzeig. xix. 1896, pp. 188-4. 



3c 2 



