ANTJRIDA. 399 



of the abdomen it is largely developed, and in places it 

 closely embraces tlie gut and also attaches itself at many 

 points to the hypodermis. In the thorax it is much 

 broken up by the various muscles ; two principal masses 

 occur in close contact with the fore-gut, one on either 

 side, and come in contact with each other in the mid- 

 dorsal line just above the heart. Prolongations of the 

 fat-body pass from the thorax into the head and partially 

 surround the cephalic glands (■fig. 63) ; they do not extend 

 forwards in front of the brain. The organ is also present 

 in many parts in the form of a thin layer of tissue situated 

 in close apposition with the hypodermis and separating 

 the latter from the body-cavity. In this form it is 

 principally developed along the ventral side of the body, 

 especially in the thorax. 



The fat-body is limited exteriorly by a layer of con- 

 nective tissue and, where it is in contact with the hypo- 

 dermis, this investment is directly continuous with the 

 basement membrane of the body-wall (fig. ,16). It is 

 wanting, however, from that surface of the fat-body 

 which is in close contact with the hypodermis and other 

 parts of the body. 



In a newly hatched Anurida, before any active 

 process of excretion has taken place, the fat-body is seen 

 to be composed of masses of large cells with very irregular 

 boundaries (fig. 18). These cells are composed of a some- 

 what granular protoplasm, and each contains a relatively 

 small nucleus. The first indication of excretion taking 

 place is seen in the fact that many of the cells undergo 

 liquefaction at their centres, and eventually become 

 vacuolated (figs. 18 and 19). These vacuoles frequently 

 become confluent with one another, and the remaining 

 protoplasm, together with the nuclei, becomes restricted to 

 the periphery of the cells. At a later stage, there appear 



