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The Ephippia of the Lynceid Entomostraca 

 By D. J. ScouRFiELD, F.R.M.S. 

 {Read December 2Wi. 1901.) 

 Plates 10, 11 and 12. 



For some years past I have been making observations, as 

 oiDportunity ofiered, on the protective coverings of the winter or 

 resting eggs of the Cladocera, known in their more highly 

 developed forms as " ephippia." I have already in two papers 

 read before this Club brought forward some of the facts ascer- 

 tained—see "The Winter Egg of a Rare Water- Flea " (10)* 

 and "The Ephippium of Bosmina" (11)— and it was my 

 intention to wait until I had sufficient material for a paper on 

 ephippia in general before writing anything further on the 

 subject. As, however, I have not as yet been able to do much 

 with the ephippia of the Daphnidae and nothing at all with those 

 of the Lyncodaphnidae, while on the other hand I have now 

 collected a fair amount of information on the ephippia of a large 

 proportion of the genera of the Lynceidae, it seemed advisable to 

 put together my notes on tiiis family rather than wait for an 

 indefinite period until I should have been in a position to deal 

 in a suitable manner with the ephippia of the whole of the Order 

 Cladocera. There is also some further justification for this 

 course to be found in the fact that the Lynceid ephippia are 

 not nearly so well known as those of the Daphnidae, and they 

 seem, therefore, to call more urgently for consideration. 



It is somewhat surprising, indeed, that a greater amount of 

 attention has not hitherto been paid to the simple types of 

 ephippia found among the Lynceidae. The explanation is 

 no doubt due to several causes, the chief of which are probably 

 the comparative rarity of the occurrence of these structures, their 

 small size, and the somewhat mistaken notion held by students 

 of the Cladocera that the ephippia of this family are practically 

 unmodified carapaces and not specially prepared receptacles 

 intended for the protection of the winter eggs. 



* The figures in brackets refer to the number in the list of literature 

 appended to this paper. 



