XI 



SEGMENTATION 



289 



and of a pair of long pointed pieces which project on to the next 

 segment. Just as in the case of the genital operculum the bn.sil 

 1 1,1 it is united in front to the appendages, the remainder IK 'in-- 

 free, and separating the greater part of the two plate-like append- 

 ages. In the complete animal the median process of this segment 

 is covered by the median process of the genital operculum. The 

 remaining appendages of the female, and all the appendages 

 behind the operculum in the male, are without any median 





B 



FKI. 163. Kiii-ii/ilci-ns fischeri., Eichw. Upper Silurian. (After Holm.) A, Genital 

 operculum of male ; a, median process. B, Middle part of second appendage ..t 

 tlie inesosoma in tlie female, showing the median process. 



process, and the plates of each pair unite by a suture in the 

 middle line. 



The metasoma (Kig. 101, 13-is) consists of six segments 

 which become longer ;md narrower from before backwards. Ivn-h 

 M'oment is covered bv a rinir-likr slnMth <r sclt-ritc, ;md bears ID 



O i/O 



ap]iciid;igfs. The posterior end of the lust si'-mmi i produced 

 into a lobe on each side, and between these lobes the Ion-, imrrow 

 tail-spine arises (Fig. 101, 10). 



The other genera of the Kiiryptenda do not differ in ;mv 

 important morphological respects from the form just described, 



VOL. IV ' 



