392 



INVERTEBRA TE MORPHOLOO T. 



upon the sides of the body and forming a long cylindrical 

 uujoiuted appendage. 



Respiration is usually effected by the general surface of 

 the body and the inner walls of the shell duplicature, though 

 in certain Cypridiuidse a double row of respiratory processes 

 are situated upon the dorsal surface of the body near the 

 second thoracic appendage. The so-called branchial lobes on 

 the maxillae probably subserve the respiratory function only 

 by renewing the water in contact with the body surface. A 



H 



Sm 



1) 



FIG 176. Cypridina tnediterranea, FEMALE (after GLADS). 



At 1 = auteuuule. 

 At 1 antenna. 



h heart. 



Mnp mandibular palp. 

 Mx\ MX- = first and second maxilia. 



o simple eye. 

 Oc = compound eye. 

 Pr = frontal organ. 

 Sm shell-muscle. 

 t l , T* = first and second thoracic 

 appendages. 



single median eye alone is present in Cypris and Cythere, but 

 in addition a pair of lateral compound eyes occurs in Cypri- 

 dina. The frontal sense-organ is a single strong process, in 

 certain forms lying slightly above and between the autemmles. 

 A heart is present in Cypridina and Halocypris as a saclike 

 organ with two lateral ostia and is not prolonged into arteries. 

 In Cypris and Cythere it is entirely wanting. 



The Ostracoda occur both in fresh water and in the ocean. 

 The genus Cypris and its allies are for the most part aquatic, 

 while the other genera mentioned are exclusively marine. 



