244 



ZOOLOGY OF THE FAR EAST. 



fine grooves, to be seen only under a strong lens. The epigastric crests are promi- 

 nent ; their anterior edges are strongly and irregularly rugose and they are separated 

 in the middle by a deep grove which, however, does not extend backwards behind 

 them. The protogastric or post-orbital crests are practically obsolete, being repre- 

 sented merely by a slight roughened declivity separated by a faint transverse depres- 

 sion from the upper orbital margin. Internally the crests are on a line with, and 

 only indistinctly separated from, those on the epigastric region ; from this point they 

 slope backwards on either side, completely disappearing before reaching the lateral 

 margin. The upper border of the orbit is practically smooth ; the lower margin is 

 beaded and there is a distinct sinus beneath the outer orbital angle. The front is 

 faintly emarginate in the middle and its breadth is contained about two and two- 

 thirds times in that of the carapace. The edge is very finely crenulate and the upper 



Fig. 5. — Potamon {Potamon) anacoliithon, sp. nov. 

 Male, 178 mm. in breadth of carapace, and eggs of female drawn to same scale. 



surface finely rugose. The epibranchial tooth is very strong and is situated at some 

 distance from the outer orbital angle ; the surface in its vicinity is distinctly roughened. 

 The level of the carapace in front of the epibranchial tooth is the same as that behind 

 it. The margin between the tooth and the outer orbital angle is beaded ; behind 

 the tooth it is finely denticulate. The postero-lateral walls bear a few fine oblique 

 striae ; the lower surface, on either side of the buccal cavern, is covered with short 

 rugae from which small setae arise. 



The ischium of the outer maxillipedes is traversed longitudinally in its middle by 

 a fine and deep groove ; it bears very large punctae, especially near the antero-inter- 

 nal angle. The merus is much broader than long, with raised outer and inner borders 

 and with its antero-external angle rounded off. The basal portion of the exopod 

 reaches to the middle of the merus; the flagellum is very long. 



