On the Oenus Ortmannia, Railib. 377 



Promachus (?) bicolor, sp. n. 



Long. Corp. 55-57 mm. 



Male. — Rufous ; the antennte, spines, a broad band down 

 the middle of tlie body, bisected by the rufous carina, an 

 interrupted lateral line, and the legs beyond the apical fourth 

 of the femora black or blackish. Head with two pairs of 

 spines near the back ; pronotum deeply sulcated before the 

 middle, with a pair of long spines on the front lobe and small 

 lateral ones at the front angles, and two pairs of spines (the 

 first longest) on the second lobe. Mesonotum with five pairs 

 of spines (the last pair approximating) on the central region, 

 and a row of six spines on each side on the lateral black line ; 

 metanotum, median segment, and several of the basal seg- 

 ments of the abdomen with a pair of central spines, diminish- 

 ing in size hindwards ; there are also two strong lateral spines 

 on the metanotum and two on the meso- and metapleurge. 

 Segments of the abdomen hardly twice as long as broad ; 

 hind legs rather longer than the others, extending as far as 

 the extremity of the seventh segment of the abdomen. 



Female (?) . — Larger and stouter ; testaceous, mottled with 

 blackish; the spines arranged nearly as in the male; legs 

 shorter, stouter, and carinated ; hind femora extending rather 

 beyond the fifth segment of the abdomen ; abdomen with a 

 sinuous carina on the sides of the segments, segment 10 

 tripartite at the extremity ; except the front lobe of the pro- 

 notum, the whole median line of the thorax and abdomen is 

 traversed by a very strong raised carina. Abdomen without 

 terminal spine ; operculum not projecting beyond the last 

 segment. 



JIab. Tonkin (Than Moi), June and July (Fruhstorfer) . 



XLIIL — On the Genus Ortmannia, Rathb., and the Mutations 

 of certain Atyids. By E. L. Bouvier *. 



The shrimps of the family Atyidse belong exclusively to 

 fresh water. Despite their adaptation to this special medium 

 and the strange aspect of their most typical forms, they 

 attach themselves by a series of genera to the most primi- 

 tive of the marine shrimps. From Xiphocaris, of which the 

 chelffi are normal and are furnished with exopodites on all 

 the feet, one passes to Atycephyra, in which the exopodites 

 have disappeared on the three posterior pairs of feet, to 

 Caridina, which have no expodites and whose anterior 

 * Translated from the ' Comptes Rendus,' t. cxxxviii. p. 446. 

 Ann. & Mag. N. Hist. Ser. 7. Vol. xiii. 25 



