i 



Mr. H. J. Carter on the Organization of hifusoria. 119 



Sarcode. — This name was proposed by Dujardin for the 

 '^ glutinous substance of the interior" of Infusoria*; and we 

 shall here understand it as applicable solely to what, in other 

 words, might be termed the " abdominal mucus " (figs, lb, 2 b, 

 3 b). The sarcode occupies the centre, while the diaphane and 

 pellicula form the circumferential layers of Infusoria; besides 

 this, it is the seat of the " granules " and other organs of the 

 interior, and appears to receive the food directly into its sub- 

 stance. From the greater latitude of the particles which are 

 situated towards the centre, that portion may be inferred to be 

 of less density than the rest ; and sometimes, when the animal- 

 cule is rendered spherical by aqueous distension, there appears 

 to be an actual cavity here (fig. 2 d) ; but as I am not certain 

 about the real situation of the water under these circumstances, 

 I shall return to this point again by-and-by. In the Rhizopoda 

 generally, the sarcode appears to have no external communica- 

 tion, and hence the food must pass into it directly through the 

 diaphane ; but in most of the other Infusoria it communicates 

 with the surrounding medium by one orifice at least. The same 

 kind of substance occupies a good portion, if not the whole, of 

 the internal or abdominal cavity of Astasia and Euglena, Vorti- 

 cella, Paramecium, and the Infusoria of this class. When death 

 is about to take place, it comes forth from Vorticella, Parame^ 

 cium, &c. in round, transparent, structureless expansions; and 

 even during life in Stentor a portion may be made, by pressure, 

 to issue through a rupture of the pellicula without any apparent 

 injury to the animalculef. Otostoma%, also, when under press- 

 ure, throws oiF portions of its sarcode through the anal orifice, 

 containing a number of the '' spherical cells,''' to be mentioned 

 hereafter, with which it is charged in this kind of infusorium. 

 As we shall presently find that the portions of food which are 

 received into the midst of the sarcode are circulated round the 

 abdominal cavity, it seems necessary to admit, also, that the 

 sarcode is endowed with a power of motion, in which we cannot 

 help seeing an analogy to that motion which exists in the ali- 

 mentary canal of higher animals. 



In Euglena the sarcode is separated from the diaphane by a 

 layer of pointed, sigmoid fibres, arranged parallel to each other, 

 so as to form in Crumenula texta, Duj., a conical cell, which, as 

 soon as the ovules have become developed, and the diaphane and 

 other contents of the sarcode have died off", becomes transparent, 

 but still retains its conical form until the resiliency of the fibres, 



* Op. cit. p. 35. 



t Ehrenbcrg, ap. Dujard. op. cit. p. 34, footnote. It is the same with 

 Nassula. 



X Auu. & Mag. Nat. Hist. vol. xvii. pi. ix. figs. 6-8, 1856. 



