CRUSTACEAN LEG SEGMENTS — CARPENTIER & BARLET III 



On the whole we see thus that the equivalents of the majority of 

 the endosternal arms of the Apterygota and particularly those which 

 had appeared the most consistent and typical, have been found in 

 Penaeus. The importance of this result is obvious. 



We have now to describe the subhypodermal scaffolding of Anas- 

 pidcs (fig. 7). In spite of the great differences which it displays at 

 first sight from that of Penaeus and in spite of its relative sim- 

 plicity, it furnishes us on many points valuable information for the 

 interpretation of the cuticular skeleton to which it pertains. In 

 Anaspidcs, the endoskeleton is not unified; no strip h connects the 

 right formation with the left formation. Each of them contains two 

 superior blade-shaped arms, one {sa^) pertaining to the front of 

 the tergal region, the other {sa-) arising from the back of the 

 same region and in the proximity of which it is particularly wide. 

 The two arms do not pertain to phragms but to "pseudophragms" 

 ( subhypodermal ) . 



There are two lateral arms, and these are the most interesting. 

 One of them {p) connects the endosternite with what we have inter- 

 preted as the process of the pleural apodeme {pp). This arm is inter- 

 esting, first because it confirms our interpretation, then because of its 

 shape: it is a sheath of the process, a sheath of the same type as 

 (although smaller than) the "fourreau" which fits the long pleural 

 horn of the Machilidae (Carpentier, 1946, fig. 6, and 1949, fig. i). The 

 other lateral arm {d), no shorter than the preceding one, is attached to 

 what was supposed to correspond to a postpleural process {ps). Our 

 supposition becomes thus a certainty. 



If we really have to do with a postpleural process, it becomes obvi- 

 ous that this formation does not pertain to the precoxopodite but to 

 the upper sclerite, the laterotergite. It seems to us that this sclerite, 

 already present in Anaspides, must represent the anapleural region 

 of the Apterygota. In keeping with this opinion, we have to discuss 

 the following facts: In Penaeus (fig. 4) and other Malacostraca we 

 have found a muscle (bs-ps) of the basipodite (trochanter) coming 

 from the under part of the postpleural process. In the Machilidae we 

 have recently found out that in the prothorax (fig. 5) a few fibers 

 (tr-an), very close to those of the depressor of the trochanter (Barlet, 

 1946, fig. 2, TR-ED), come from a sclerite (ibid., sp) to which the 



not been correctly located. Our researches after 1946 have shown that instead 

 of "/ -}- e" we should have written "//' and instead of "i + d" we should have 

 written "e + d." 



