24 



TAfiE SK()(lSI!Kli<; 



The morphological 

 f/ilueofthedil/ercnl 

 riirls of ihc /xisl- 

 ,,nil 1 1 ml)!' of I III' 

 f'riisliirffi. 



But iu a miiiiber of t-ases, liowpvcr, tlie rod-shaped limb aj)|)t'aT.s tu liavo dewloi.ed directly I'ruiii 

 the foliaceous type. As an instance of this W. (JlBSBHECirr mentions, 1913, p. 33, among other 

 things. „die stabbeinformigen hiiiteren Maxillen uiid die iihnlichen Tlioraecipodien mancher 

 s t r a c o d e n"; for these forms see below. 



It seems however, to be by no means impossible that the development has sometimes 

 procedcd in the opposite direction, that, for instance, more or less foliaceous limbs have been 



developed from biramous or rod-shaped limbs. Thus, 

 even if we accept the assumption that the foliaceous 

 type is the primitive one in the Crustacea, we are not 

 bv any means justified in assuming a priori that we 

 have an original type every time we meet this limb. 

 With regard to what might be called the 

 morphological value of tlie different parts of the 

 Crustacean post-oral limbs opinions also still differ. 

 Thus E. KORSCHELT and K. Heider, in their work 

 of 1890, are of the opinion that the exopodite and 

 the endopodite are organs of equal value — they refer 

 them, as we have seen above, to the two main branches 

 of the Annelidan parapodium: when in a number of 

 forms, especially among the Malacostraca, the endo- 

 podite forms a direct continuation of the protopodite, 

 while the exopodite appears in the forni of a more or 

 less reduced ajipendage, this is — according to these 

 authors — not to be considered as a primitive con- 

 dition; cf. loc. cit. 1). 388. On the other hand, accor- 

 ding to these two authors the epipodial appendages 

 are of a differcMit nature from the exopodite and endo- 

 podite; they are, as we see above, p. 22 homologized 

 witli the dorsal cirri on the Annelidan parapodium. 

 J. TlliEi.i': protests against this view; in his 

 work of 190.5, p. 466 he writes as follows: ,,Dazu be- 

 merke ich zimachst, daB nach meiner Auffassung die 

 bi'idcn Aste, Endopodit iind Exopodit, urspriinglich durehaus nicht gleichwertig sind, sondern 

 (let- cisteic die einfache Fortsetzung des Stammes, der letztere ein Anhang desselben, daher 

 kann man sic nicht wohl auf die gegabelte Gestalt der Parapodieu zuriickfiihren , sondern den 

 Basipoditcn mit dem Endopoditen auf deren 8tamni. d(>n Exo])odit('n auf oinen dorsal(>n 

 .Anhang, etwa einen Cirrus." 



Neither of these two alternatives can hv said to be j)r()ved in anv way. So far both are 

 tn l)c (■on>^i(h'rcd as assumptions. 



I n ni y o p i n i o n t li ere c o u 1 d o r i g i n a 1 1 v s c a r c o 1 v li a- v e been 

 a n y c s s c ii t i a I m o i' |( h o 1 o o i c a 1 d i I' f c r c n c c cit h c i' b c t w c en c x i t c s 



Vvx. 



•I'll 



r ..Si'iiiik! tlldluric I'mil" ( 

 riiiirrif/iriiiis Sciiaff. 

 ( I'lmii 1! \v [,\NKi;sTKii. ISSI 1. 



r A/Jh 



