CERATIUM 771 



forms of the cilio-flagellate group belong to the genus C&ratiwm (fig. 

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

 In the Ceratlum tripos (1) 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 spinous. In Ceratium 

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

 < me 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 withdrawn.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 litile flattened, 



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

 Ann. Xi/t. Hist. ser. iii. vol. xviii. 1866, p. 4-29 ; Bergh, MorplwL Jahrbiich. vii. 1881. 

 P. 177, and Vanhliffen, Zool. Anzeig. xix. 1896, pp. 133-4. 



3c 2 



