HUXLEY, ON DYSTERIA. HI 



mass of " sarcode/^ in which the ingested matters are im- 

 bedded^ and no clear evidence could be obtained of the exist- 

 ence of any digestive ca\ity with distinct walls. 



A little behind the middle of the body, and towards its 

 ventral edge, there is a clear spheroidal "contractile space" {d), 

 which varies a good deal in size. One measured X3'575th of 

 an inch in diameter, and became entirely obliterated in the 

 contracted state. 



The contractions are not rhythmical, but take place irre- 

 gularly. On the approach of death the space becomes irre- 

 gularly and enormously enlarged, until it occupies perhaps a 

 thii'd of the whole contents of the body. 



Immediately beyond the contractile space there is a cui'ious 

 oval body (e), having its long axis (jo'oo ii^O directed upwards, 

 and containing a comparatively small central cavity, so that 

 it appears like a thick-walled sac. 



Indications strongly suggestive of an inferior opening were 

 sometimes observed in this body, but no demonstrative 

 evidence of the existence of any such aperture could be 

 obtained. 



The walls of the ventral groove are provided with long and 

 powerful cilia, a remarkably strong one being attached behind 

 the base of the " appendage," and by their means the animal, 

 when free, is propelled at no very rapid rate through the 

 water. Its more usual habit, however, is to remain fixed by 

 means of the peculiar appendage (/), and then the cilia act 

 merely in creating ciuTents, by which nutritive matters are 

 brought towards the mouth. 



The appendage referred to is attached to the surface of the 

 body, rather towards the convex side, at the bottom of the 

 ventral groove, and is distant about one fifth of the whole 

 length from the posterior extremity. It is -^IqWi to ToVcith 

 of an inch in length, and is not altogether milike a boot, with 

 a very pointed toe, in shape ; and the toe appears to be viscid 

 at its extremity, so as readily to adhere to any foreign object. 

 The appendage then forms a pivot on Avhich the whole body 

 turns about, and this appears to be the habitual and favorite 

 position of the Dysteria. 



Internally, the appendage contains a canal {g) , wider above 

 than below, and apparently blind at each extremity. 



No "nucleus" could be found, though carefully sought for 

 with the aid of acetic acid. 



The occurrence of transverse fission was noticed very 

 distinctly in one case ; but it is remarkable that, notwith- 

 standing the great number of specimens which were observed, 

 no other instance of this mode of multiplication came under 



