40 Annals of the South African Museum. 



Zool. Soc. London, p. 363), he had named Macrobrachium. In 

 reviving the name for a sub-genus or " group," Ortmann does not 

 appear to have included under it any of the species originally 

 assigned to it by Bate himself. The first of these was M. 

 americanum, which in Ortmann's system becomes Palcemon (Brachy- 

 carpus) jamaicensis (Herbst), and is named Bithynis jamaicensis 

 by Miss Eathbun in 1901. Bate's M. formosense and M. longi- 

 digitum are referred to Eiipalcemon, M. africanum is made a 

 synonym of Bithynis (jaudichaudii (Milne-Edwards). M. gangeti- 

 cum, insufficiently described, is not mentioned, but would probably 

 be referred to Eupalcemon. Under the circumstances the retention 

 of the hybrid name Macrobrachium does not seem justifiable, and 

 I have substituted for it a name implying that in this genus one 

 member of the pair of large chelipeds decidedly exceeds the other 

 in size. 



Coutiere says : " The group Macrobrachium is well characterised 

 in general by the palm [of the second peraeopods] compressed, 

 oval, broader than the carpus at its distal end, which gives the 

 most differentiated species of this group the aspect of Astacidae 

 (P. lepidactylus). The carpus and meropodite, each distally inflated, 

 are in general nearly equal." He adds the caution that young 

 forms, and also the adults of certain species, resemble species of 

 Parapalcemon and Eupalcemon by the feeble compression and small 

 breadth of the palm. 



MACROTEROCHEIR LEPIDACTYLUS (Hilgendorf). 



1878. Palcemon lepidactyhis, Hilgendorf, Monatsb. Akad. Berlin, 



p. 838, pi. 4, figs. 14-16. 



1891. Palcemon lepidactylus, Ortmann, Zool. Jahrb., vol. v., p. 735. 

 1905. Palcemon (Macrobrachium) lepidactylus, Coutiere, Ann. Sci. 



Nat. Ser. 8, vol. xii., p. 272, pi. 10, pi. 11, figs. 13, 13a. 



Coutiere includes in the synonymy Palcemon lepidactyloides, 

 de Man, 1892 (in Max Weber's Zool. Ergebn. Niederl. Ost-Indien, 

 vol. ii., p. 497, pi. 29, fig. 51). The careful comparison which he 

 institutes of a large number of specimens makes it fairly certain 

 that there is no need for two specific names. 



In a large dried specimen from the Durban Museum the rostrum 

 has 13 teeth above and 2 below, its apex fully reaching the end 

 of the peduncle of the first antennae, the teeth not nearly reaching 

 the middle of the carapace. The great left-hand cheliped has a 

 total length of about 190 mm., the movable finger being 45 mm. 



