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T^The Sympoda (Part VI. o£ S.A. Cmstaoea, fo,^ the Marme 

 Invest gations in South AIrica)*.-By the Eev Thomas E. B. 

 STEBBik M.A., F.E.S., F.L.S., ^-Z-S' I^Tt t Z 

 College, London, Hon. Member of New Zealand Inst., Hon. 

 Fellow ot 'Worcester College, Oxford. 



The Sympoda are a group in many ways remarkable. Its bound- 

 a"es are at present as sharply defined as any systematist cou d 

 possiblv wish All known Crustaceans are either dearly Sympoda 

 or cleariy uot Sympoda. None hover doubtfully on the outsku-ts of 

 thi society On the other hand, within its lim.ts the relat.ons are 

 hi hy p rplexmg. There is so much mterlacing of characters 

 toitber wfth so many fine gradations, that any settled standard o 

 c a's ificat on is difficrdt to adopt, or ,f adopted to uphold agamst 

 ::„ ble objections. For d.stinguishing tamUies P- -1 -n 

 venience solic ts a choice of external and easily observable teatmes. 

 T e w,"e y eparated eyes of Nan,u..tacus offered such a character, 

 " It^e klfdred C,.,,.«a was found with a single eye. ^be presence 

 or absence of a distinct telson sets one group of families m a marked 

 manner apartfromanother group. Yetbetween the greatly elongated 

 Tegmen' '" Makrokylindrus and the disappearance of the segment in 

 BfZna there are not a tew intermediaries, so that a compai-ative y 

 short and narrow telson in LaptoUylis leads on through a short and 

 WuTt one in Petalosania to forms in which the telsonic segment , 

 Toduced between the uropods, though the produced part is not 

 ZtZU and in Eud.reUop.s BipUcam. Caiman, this unarticu- 



ted portion is marked off "^y ^^ ^^''-'']^'^!:'J^ ^^^ 

 In some of the appendages the third or ischial 1°" '^ fP' ^ 

 disappear Accordingly its presence or absence seemed hkely to be 

 St for classiftcatory purposes. But this proved disappointing, 

 tette! though the ioint is often quite definitely present, and some- 



. r.,. ,.-iii. >.-e -«^p-'^!■ft;"„;^;:?■z:,;Ttrr.h\?:;::' 



