152 ZOOLOGY 



range of the invertebrate animal kingdom (Mollusca, Saccocirrus, 

 Scorpions, Spiders, Insects. Myriapods, Oniscus). It must be 

 said in criticism, however, tliat there is a considerable degree of 

 difference between these authors on the exact method of elabora- 

 tion of the fatty yolk spheres. To quote examples of this, the 

 spheres may be apparently secreted by the Golgi rods, the latter 

 remaining on the outside of the spheres (Gatenby and Woodger in 

 Patella (41), Ludford in Patella (74) ) ; on the other hand the 

 Golgi bodies may swell and so be metamorphosed into yolk, 

 having the fatty substances deposited within them (Brambell in 

 Helix (15), Nath and collaborators in Scorpions (96, etc.), etc.). 

 A further complication arises in this connection because Nath 

 has adopted Parat's views as regards the " vacuome " and Golgi 

 apparatus. He therefore refers to the neutral red staining vacuoles 

 as Golgi bodies, and that these swell and fill with fatty substance. 

 Gatenby has shown (35) that although these vacuoles may be 

 associated with the Golgi apparatus and may therefore be present 

 in the idiosome (so that Nath's results would coincide with the 

 first type of fatty yolk formation by Golgi), the vacuoles may have 

 no intimate relationship with the Golgi bodies by the time fat is 

 being deposited in them. Nath is therefore possibly (but not 

 probably) examining some other cytoplasmic inclusion. 



Turning now to the second group of opinions, we find that the 

 only point in common between them is that they all agree that 

 fatty yolk is not formed by or from the Golgi bodies. Instead, 

 cytoplasm (Weiner in Lithobius), cytoplasm and nucleolus (Harvey 

 in Carcinus), material from test-cells compounded by mitochon- 

 dria (Harvey in Ciona), " yolk nucleus " (Koch), vitelline layer of 

 cytoplasm (Weiner on Tegenaria) are all invoked in turn as sources 

 or instruments to form the fatty yolk. 



It will thus be seen that there is no opinion on the matter which 

 can be mentioned as generally accepted. 



With regard to the albuminous or proteid yolk there is more 

 general accordance in some ways, although here again there is a 

 strong minority. Starting with Hogben (on Periplaneta, Synergus, 

 Formicus and Libellula), who found that nucleolar extrusions were 

 intimately related with the formation of albuminous yolk, others 



