TITANOSOMA AND POLYMICRODON IN ENGLAND l6l 



ever, that these French examples do represent a distinct form, 

 this distinction must be renewed and confirmed by other 

 characters which are dealt with in what follows. 



The relationship of Polymicrodon latzeli with Macheirio- 

 phorori is expressed in both gonopod segments. I would here 

 refer especially to my thirty-seventh paper on the Diplopods, 1 

 on " Deutsche Craspedosomiden," since I have there con- 

 cerned myself specially with Macheiriophoron. The coxites of 

 the anterior gonopods in this genus I have discussed on pages 

 28 and 29, where I state, "the coxites remind one not a little 

 of those of Polymicrodon; they possess especially, like those 

 of that genus, a comb-like section, which in Macheiriophoron 

 is placed upon a laterally compressed leaf-like structure which 

 I will call the sickle-plate, because it is always hooked over 

 towards the rear more or less in the form of a sickle, with a 

 process directed backwards. Anteriorly these coxites are 

 hollowed out into thick flaps, whilst at the base of the sickle- 

 plates a side-arm rises up." These laterally compressed sickle- 

 plates, which with their processes and points are backwardly 

 directed, remain in Macheiriophoron completely separated in 

 the middle line, so that in this genus we cannot speak of a 

 syncoxite. Although there is a distinct syncoxite in Poly- 

 microdon, there is yet a resemblance in many points with the 

 coxites of Macheiriophoron, for here also we have parts 

 which we can not only describe as sickle-plates, but which 

 correspond in structure; for we have, as illustrated in 

 pi. X., fig. 4, a comb-like section (gr), a large, pointed process 

 (s) projecting over it, a deep cavity formed by these two parts, 

 and at the proximal side of the cavity a shorter process (z), 

 and finally also thick cushions (p) at the base of the coxites. 



We must not, however, forget a number of considerable 

 differences from Macheiriophoron, and these appear in the fact 

 that in the cavity of the sickle-plates there stand, not short 

 and simple points, but long rod-like awns, whilst shorter 

 spikes, easily overlooked (X. 6, b), project at the base of 

 these awns. Further, the sickle-plate does not end in two 



1 Sitzungsberichte d. Gesellsch. nat. Freunde, N. 1, 1910, Berlin. 



