ARTHROPODA 



267 



which covers the body of the animal is invaginated at the 

 mouth, and lines the gullet and the anterior third of the 

 stomach. The rest of this organ is lined by large columnar 



Fig. 159. — Longitudinal vertical median section through Cyclops, partly 

 diagrammatic. After Hartog. 



1. Cerebral ganglion. 7. Proctodaeum. 



2. Ventral nerve cord, ganglion omitted. 8. Ovary. 



3. Mouth. 9. Uterus. 



4. Stomodaeum. 10. Spermatheca. 



5. Cells lining posterior part of stomach. H. Eye. 



6. Intestine. 



cells, some of which contain fat globules, and others granules 

 which pass into the intestine, and so out of the body. These 

 granules have been regarded by some authorities as urinary. 

 The intestine stretches from the stomach to the hind end of 

 the second abdominal segment, and then passes into a rectum, 

 which is lined with a chitinous cuticle continuous at the 

 anus with the general chitinous covering of the body. No 

 liver diverticula open into the alimentary canal of Cyclops, 

 although these structures are found in some other Gnatho- 

 stomata, but there are a pair of salivary glands which open 

 by a common duct into the oral face of the labrum, a process 

 which overhangs the mouth anteriorly. 



No heart exists in Cyclops, but the space in which the 

 alimentary canal lies contains a colourless fluid, in which 

 colourless corpuscles float. The space which contains this 

 fluid is much broken up by connective tissue trabeculae and 

 strands of muscle, which support the alimentary canal and 

 generative organs. The various muscles are striated, and their 

 contraction causes the stomach and intestine to move rhythmic- 



