64 



INVERTEBRATE ZOOLOGY 



form into the germ cells. Morphologically, the female germ cells 

 become differentiated from ordinary epithelial cells chiefly 

 through the addition of deutoplasm or yolk and in many instances 

 through acquiring additional membranes. On the other hand, 

 the male germ cells become highly modified and undergo exten- 

 sive rearrangements of their parts, chiefly as an adaptation for 

 more effective movement. 



Connective or Supporting Tissue 



Definition. — Tissues which fill in between and connect other 

 tissues, give support to them and to the body in general, are 

 grouped under the general category of connective or supporting 



tissues. It has been shown that 

 the individual cells in their form 

 and function give the chief char- 

 acter to epithelial tissues, but in 

 the connective tissues plasmic 

 products are usually the most 









Fig. 40. — Cartilage of an adult 

 squid. {Frorn Dahlgren and Kcpner, 

 courtesy of The Macmillan Company). 



/' 



Fig. 41. — Portion of a section of 

 Cerebratulus marginatus, showing much 

 branched connective tissue cells. 

 {After Schneider, courtesy of Gustav 



Fischer) . 



conspicuous elements. In some tissues these products are 

 intracellular as in the spicules formed by certain cells of the 

 sponges. Fat or adipose tissue results from an accumulation of 

 oil or fat droplets within the cytoplasm until they coalesce to 

 form a single large drop around which the cytoplasm of the cell 

 is spread in a thin, attenuated layer. 



