222 ZOOLOGY OF THE FAR EAST. 



Since 1849^ when the concluding part of de Haan's magnificent work on Japanese 

 Decapod Crustacea was pubHshed, a considerable number of important papers on the 

 same subject have appeared, notable contributions having been made by Doflein, Miss 

 Rathbun, de Man and Balss. The present collection does not in consequence make 

 any striking addition to our knowledge of the non-marine forms, though it has been 

 possible to demonstrate the existence in the main island of Japan of two distinct races 

 of Xiphocaridina (more correctly Paratya) compressa. 



Compared with Japan, China is from a carcinological point of view almost un- 

 known and the collections from this country are in consequence of very great interest. 

 Sixteen species were found in three distinct localities, all having been obtained in pure 

 fresh water. 



Tai Hu Lake, Kiangsu Province. (V,;- 



Rhynchoplax introversus, Kemp. Palaemon nipponensis, de Haan. 

 Eriocheif sinensis {Milne-'Eà^a.ràs). „ asperulus, von Martens. 



Potamon [Potamon) denticulahim (Milne- [^Leander modestus, Heller. 



Edwards). ■ '-'- Caridina denticulata, subsp. sinensis, nov. 



Shanghai and the Whangpoo River. 



Tympanomerus deschampsi, Rathbun. Sesarma dehaani, Milne-Edwards. 



Eriocheir sinensis (Milne-Edwards). •■Leander'annandalei/K.em.-p. 



,, leptognathus, Rathbun. „ modestus, Heller. 



Sesarma intermedium (de Haan). Palaemonetes sinensis (SoUaud). 



Caridina nilotica subsp. gracilipes, de Man. 



The Peak, Hongkong. 

 Potamon {Potamon) anacoluthon, -sp. nov. Caridina serrata, Stimpson. •' 



It will be noticed that nine genera are represented in this collection, a very large 

 number when it is remembered that all were found in fresh water. Three species and 

 one subspecies had not previously been described ; of these the Rhynchoplax is interest- 

 ing in view of its habitat, while the Leander is of considerable importance in that it repre- 

 sents a type intermediate between Henderson's very remarkable L. tenuipes and the 

 more normal members of the genus. Tympanomerus deschampsi, Eriocheir leptogna- 

 thus and Palaemonetes sinensis are species only recently discovered ; but our know- 

 ledge of Palaemon asperuhis, Leander modestus, and Caridina serrata has hitherto rested 

 on descriptions made more than fifty years ago. Caridina nilotica subsp. gracilipes 

 is recorded far to the north of its previously known range and evidence is brought 

 forward to show that the Chinese form of Caridina denticulata differs sufficiently from 

 that found in Japan to warrant subspecific recognition. 



The only species in Dr. Annandale's collections common to both China and Japan 

 are Sesarma dehaani and Palaemon nipponensis. 



The collection from the Tale Sap, a lagoon connected with the Gulf of Siam by 

 means of a comparatively narrow channel, contains the largest number of species, 



