Introduction to Am mat MorpJiology. 333 



and Stomapoda).* The hepatic cells are yellow or 

 brown, and contain oil globules. Similarly colored 

 cells may form patches on the wall of the chyle- 

 stomach. The intestine is short, straight (except in 

 Cladocera), sometimes sacculated (Sapphirina), and 

 possessing caeca ; rarely villous in patches (Gyge), or 

 marked on its inner wall with longitudinal grooves 

 (Isopoda). The anus is terminal, ventral, except in 

 Cladocera and some Copepods. In Astacus, Limna- 

 dia, Daphnia, &c., the intestine has been observed to 

 take in and discharge water rhythmically. Where 

 the chyle-stomach joins the intestine, or in the intes- 

 tine, are often cells holding concretions (of uric acid r) 

 forming a layer of limited extent. In some larvae this 

 renal area is isolated in a special caecum, which per- 

 sists in Cyclopsine Castor. 



The other secretory glands are : — i. A poison 

 gland in Argulus, seated beside the mouth, with its 

 duct opening on the proboscis. 2. The shell gland of 

 Copepoda, a coiled, fine tube on each side of the head, 

 opening by a slender duct at the base of the antenna. 

 In Phyllopods its duct opens into the mantle cavity. 

 In Schizopods and Decapods it is seated in the basal 

 joint of the antenna, and hence is called the anten- 

 nary gland, or the green pregastric gland, from its 

 colour in the crayfish. 3. The cement gland in Cirri- 

 pedia, placed at the base of the pedicles (which its 

 duct traverses) ; its secretion, poured out at the fixed 

 end of the stalk, is the medium of attachment. In the 

 Balanidae this gland is complex, and lies on the basal 

 plate of the shell, which is surrounded by the anasto- 



* There may be ten hepatic lobes, as in Stomapoda. In Decapods 

 they are combined into a bi-lobed organ. 



