130 Dr. O. Zacharias on the Reproduction and 



only from tlie dorsal side. In this case the glandular mass 

 protruding on each side certainly appears ttwlobed ; but it is 

 in reality not so, as the application of the microscope to the 

 ventral surface of the animal proves. The three glandular 

 lobes then at once catch the eye. As regards the minute 

 structure of these glands (which may best be distinguished as 

 stomach-glands) , their contents consist of a pale glandular 

 mass containing clear nuclei (with nucleoli). There can 

 hardly be any doubt that these organs are destined to pour 

 into the stomach a secretion subservient to digestion. As is 

 •well known, a similar provision occurs also on the pharynx 

 of many insect-larvae, especially in the larvae of Chironomus, 

 in which a whole circlet of such stomach-glands is always to 

 be met with. 



In the region where the oesophagus opens into the pharynx, 

 but upon the ventral side, there are always two large cells 

 (furnished with a nucleus) , which are placed close together 

 and apparently partially amalgamated. Frequently, instead 

 of one, we see two fine round nuclei in each of these two cells. 

 From the pharynx the food, crushed and mixed with the 

 glandular secretion, passes into the chyle-intestine (stomach), 

 which, in the Kotifera that I have examined, possesses a 

 distinctly perceptible intima. This is very probably to be 

 regarded as a direct continuation of the chitinous lining of 

 the pharynx. It also passes into the intestine and is there 

 particularly strongly developed. This intima is surrounded 

 "by a finely granular mass, which again is enclosed by a delicate- 

 walled tube. This mass appears to be the seat of an ahsorbent 

 faculty, for, according to the nature of the food taken into the 

 stomach, it immediately acquires a greenish, brownish, or 

 reddish colour. If the animals are left to starve the granular 

 mass gradually becomes quite decolorized, and acquires a 

 shining grey appearance. From its function it is evidently 

 to be compared with the epithelial cell-layer of the middle 

 intestine of many insect-larvae (e. g. Chironomus). As in 

 these, so in Rotifer, the source of fat-globules is to be recog- 

 nized in this absorbent layer. With abundance of nourish- 

 ment extraordinarily large oil-drops make their appearance in 

 the interior of the intestine of Rotifer. 



The intestine, as already mentioned, possesses a very thick 

 wall, and is generally tightly packed with excrement. It 

 opens outwards, together with the so-called " contractile 

 vesicle" into the doi sally-placed cloaca. 



This vesicle, on which a considerable muscular coat is 

 recognizable, morphologically represents only a dilated part, 

 corresponding to the point of union, of the two excretory 



