PHYSIOLOGY OF THE hWERTEBRATA. 55 



CcTcal appendages. Tlie ducts from these appendages open 

 into the anterior end of the alimentary canal. These Ciocal 

 appendages are not present in any of the other Australian 

 forms mentioned above. The anus in these forms is situated 

 behind or above the caudal claws. For a further description 

 of the Cladovcra the reader is referred to an excellent paper, 

 entitled "Oversigt af Norges Crustaceer med forelobige 

 Beniffirkninger over de nye eller mindre bekjendte Arter," 

 by Dr. Sars.* 



(24) The Odracoda. — " The alimentary canal of the Ostra- 

 coda is provided anteriorly with an apparatus of hard parts 

 resembling in many respects the gastric armature of the 

 Iiiopoda, aad gives rise to two hepatic caeca." 



In Cyprinotus dcntato-marginahLS, the alimentary canal 

 consists of three principal parts : a narrow, muscular oeso- 

 phagus ascending almost perpendicularly from the oral aper- 

 ture, the intestine proper, and a very short rectum opening 

 just in front of the caudal rami. " The intestine proper 

 exhibits two considerable dilatations, the anterior, lying in 

 the foremost part of the body, almost globular in form, the 

 posterior somewhat larger and more oval, both defined by a 

 well-marked median instriction, just above the great adductor 

 muscle of the shell. From the anterior division of the in- 

 testine two slender ca^cal appendages are given off, each 

 being received between the lamellas of the corresponding 

 valve and running diagonally backwards to the infero-posteal 

 corner." These caccal appendages, of a green colour, are, 

 «jj?*io?-i', pancreatic in function. The kidney or shell-gland 

 in the Ostracoda is very small. t 



(25) The Copcpoda. — The mouth leads into a straight and 

 simple alimentary canal. In Cijdops, which is probably the 

 most common form of the Copcpoda^ there is no distinct 



* C/tristiania ViiJenHhahs — Schlcaha ForliundlirKjer, 1890, No. i.pp- 30-53. 



t For a detailed description of many genera and siaecies of the Ostracoda, 

 see a paper by Dr. G. S. Bradj', F.R.S.. in the Transactions of the Jioyal 

 Sociftyof h'lfhilmr;///, vol. 35, ]). 489 ; and one by Dr. Sars in Cliri'.sf. I7(/t'««/.- 

 /SVW.-. ForhumU., 1889, Nu. 8, pp. 5-5S ; and 1890, Ko. i, pp. 54-76. 



