Xo. 4S4] 



ATTACHED YOUNG OF CRAYFISH 



263 



In the figure the dotted lines represent tlie enclosed pleopods 

 and in them the radiatinn; setie ulands in wliicli are fonnino- the 



Zeiss 2. I), these^crlands were lono- tubes from each of which pro- 

 jected a phnne.the tip of whi<-h turne.l to one side in the space 

 between the edn-e ,>f tlic plcopod and the enveloping- sac. In the 

 same way the posterior end of the telson showed lono- tubular 

 glands forniing a set of phnno>e set;c to rej)lace those already 

 present. The tip of (-i< li new ])hune j)roiected slightly from its 

 gland into the hollow ba.e of the existing plume, which' would be 



All these seta' seen in formation in long tubes are richly barhexl 



later at the next molt. ' ^ 



Only some five or six of these specimens of (\ rlarkii stirvived 

 to change into a third stage, April 29 to ^lay 1st. but these agreed 

 with all known crayfish of the third stage in tun ing a complete 

 tail-fan, with both telson and wid(>ly (>xpauded >ixth i)leopods 

 together forming a very laig-e area for n>>iMaiire to the water and 



Though these few individual. >eenied weak thev'lx.th walked 

 and swam easily. The color had now become a darker fle.di-color 

 from the crowding of red pigment c<>lls, but the area about the 

 stomach was lighter and on each side of the stomach there was 

 a small, narrow, dark band representing the yolk. 



As above stated it is ])robable that in luiture the larva- in the 

 third stage remain with the mother for a time, and then gradually 

 become entirely indej)eudent. 



Faxon. April N. 

 females withoiu . 

 Tallx.t (•o.,Marv 



