I08 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 37 



and 9"^). The processes can be connected by muscular fibers or can be 

 closely united. If the postpleuro-f ureal complex has become somewhat 

 voluminous, that with the (medio) pleural process can be found re- 

 duced or even lacking entirely. When we consider only the pterygotan 

 insects, we might think that of the two ways in which the furca is 

 united, that with the back is the more recent one. The Apterygota in 

 which this way of union (fig. 5) is so widespread,^^ the Myriap- 

 oda 22 as well as the Crustacea, lead us to adopt the opposite opinion. 

 We have now to describe and to compare with what we have just 

 seen the internal side of a precoxopodite of Anaspides. We shall use 

 the fourth pereiopod (fig. 3), that is to say, the antepenultimate leg 

 as in the previous species. The precoxopodite of this leg being free 

 and uncovered, since Anaspides does not have a carapace, it is quite 

 different from the preceding one in its orientation and in its shape. It 

 is not imbedded in the side of the thoracic segment and keeps a certain 

 mobility by means of two articulations (e, 8) with a particular sclerite 

 of the lateral wall {an). Hansen (1930) took this sclerite for a part 

 of the precoxopodite; Snodgrass (1952) named it laterotergite {Ig). 

 The posterior articulation (8), the only one seen by those authors, has 

 been interpreted by them as representing y8 of our figure 2 (Penaeus). 

 We see at once on figure 3 that there is no pleural apodeme on top of it 

 but that this apodeme (ap) is actually a part of the wall of the so-called 

 coxopodite of the authors. The curved pleural apodeme (ap) bears at 

 the top of the precoxopodite a process (pp) which may be the pleural 

 process; but, considering its position in comparison with that of the 

 process of the penaeids, we cannot yet give a definite answer. The 

 precoxal wall is divided into an episternal region (es) and an epi- 

 meral region (em) of about the same surface area. The epistemum is 

 barred almost horizontally with an apodeme which joins ap at the top. 

 Two large blades, or epipodites, are attached externally on the epi- 

 sternal region of Anaspides, while in the same region we saw but a 

 single epipodian gill in Penaeus. Finally the furcal apophysis of 

 Penaeus is completely wanting in Anaspides. The thoracic lateral 

 wall of the latter crustacean is thus rather different from that of the 

 first one; but the comparative study of the endoskeletal scaffoldings 



21 The subhypodermal endoskeleton is united with it, or connected by a tie 

 (the postcoxal tie d) at the back of the anapleural arc. See Carpentier, 1946, 

 figs. 4 and 5 (prothorax of the Machilidae), and fig. 2 {Ctenolepisma) ; Barlet, 

 1951. fig- I (Lcpisma), Carpentier and Barlet, 1951, fig. 2 (Catnpodea) ; un- 

 published (Japyx). 



22 Unpublished observation. 



