32 THÉEL, HERMAPHRODISM IN HOLOTHURIDS. 



dance of minute globules which become visible after staining 

 in acid fuchsine. The typical cells are characterized by pos- 

 sessing a number of refringent spheres easily brought to view 

 by dyeing in acid fuchsine or iron-heeraatoxyline. The spheres 

 are surrounded by a clear homogeneous protoplasm, vary 

 greatly in number and are also somewhat unequal in size. 

 Thus I counted in smaller cells only a few spheres, while the 

 larger elongated cells contain more than fifty. In properly 

 stained sections it becomes evident tbat the spheres enclose 

 one, or several smaller globules which have got a deeper colour. 

 Scattered among these cells, other migratory cells are to be 

 seen which have fewer and much larger spheres aggregated 

 so as to resemble a black mulberry. The cells in question 

 are common in all the tissues which constitute the reproduc- 

 tive organ in Mesothuria intestinalis. 



Mingled with these two kinds of wander-cells other cor- 

 puscles are met with, evidently also capable of movements by 

 means of pseudopodia, and recognised by their rounded form, 

 spherical nu.cleus, and their homogeneous plasm clear as water. 

 However, they do not seem to play any part in the resorption, 

 and they possibly represent earlier stages of one of the former 

 kinds of cells. Besides it ought to be pointed out, that we have 

 similar cells though with the nucleus now gone and replaced 

 by an irregular, small, blackish body. They are either scat- 

 tered or aggregated, particularly in such tissues which are in 

 state of resorption. The cells in question have distinct con- 

 tures, are certainly non-amoeboid and have nothing in com- 

 mon with wander-cells or leucocytes. They very much remind 

 one of fat-cells. 



In order to study the absorption of eggs and tissues in 

 Mesothuria, it is necessary to make use of very thin succes- 

 sive sections across such parts of the animal which are in a 

 more or less advanced state of destruction, to treat them with 

 some suitable dyeing solutions, and to examine the preparations 

 under a high inagnifying power. Thus, I have taken contin- 

 U.0US series- of sections through the yellowish brown small 

 protuberances and maculae placed at the posterior end of the 

 genital basis, and which have been stated to be remains of 

 former genital tubes and, besides, of sections taken through 

 tubes containing eggs in difFerent states of resorption. 



