21 



The little information given by authors as Filhol and Kirk renders the separation of 

 the species very uncertain in some cases, and the difficulty is increased by the great variation, 

 not only in the shape of the chelipeds, but also in that of the carapace, between the two sexes 

 of the same species, and even between members of the same sex. 



i. Elamcna malhaei (Desmarest). 



1825. Hymenosoma matliaei (Latreille M.S.) Desmarest. Cons. s. 1. Crust., prt 10, p. 163. 

 1830. Hy menosoma mathei Rüppell. Beschr. u. Abb. 24 Arten kurzschw. Krabben p. 21, 



pi. s, f. 1. 

 1837. Elamena matliaei H. Milne-Edwards. Hist. nat. Crust., t. 2, p. 35. 



(nee Elamene matliaei H. Milne-Edwards. Ann. Sc. Nat. (3) t. 20, 1853, p. 223, pi. 11, 

 f. 4, which is probably Halicarcinus planatus (Fabricius) ). 

 1849. Elamene matliaei Krauss. Südafrik. Crust., p. 51. 



1862. Elamene matliaei Heller. Beitr. z. Crustaceenfauna d. rothen Meeres, p. 371 '). 

 1875. Elamene matliaei Paulson. Rech. s. 1. Crust. Mer Rouge, p. 71, pi. 9, f. 3 — 3^ '). 

 1906. Elamena matliaei Nobili. Ann. Sc. Nat. (9) t. 4, p. 319. 



Several authors (see p. 19 of the present paper) have alluded to the discrepancy between 

 Milne-Edwards' description of 1837 and his figure of 1853. I have had no opportunity of 

 examining this species, the type of the genus, neither could I consult the figures of Rüppell 2 ) 

 and of Paulson. 



It is recorded from the Red Sea and from Mauritius. 



2. Elamena minuta A. Milne-Edwards. 



1873. Elamene minuta A. Milne-Edwards. Nouv. Arch. Mus. Paris, t. 9, p. 324, pi. 18, f. 5. 

 Hab. Xew Caledonia. 



3. Elamena pilosa A. Milne-Edwards. 



1873. Elamene pilosa A. Milne-Edwards. Nouv. Arch. Mus. Paris, t. 9, p. 322, pi. 18, f. 6. 



This aberrant species is remarkable not only by its large size, but especially by the 

 spine-bordered carapace and legs ; shorter spines or rather stiff hairs are distributed on the upper 

 surface of the carapace, on the pterygostomial regions, and on the much projecting extra-orbital 

 angle. The rostrum is different from that commonly met with in this genus, by being thick, 

 not lamellar, somewhat deflexed; the eye-stalks are wholly exposed, seen from above; the 

 antennules reach largely beyond the rostrum, when extended, and are not separated by a 

 prominent septum at the base. The merus of the external maxillipeds is somewhat longer than 

 the ischium. All these characters warrant the creation of at least a subgenus, but I am loth 

 to do so. At any rate the species is best recognizable among all the species of Elamena. 



The Leiden Museum contains two specimens (both cf), co-types of Milne-Edwards, from 



1) Cited after Nobili. 



2) Rüppell's paper is at my disposal, but unfortunately the plates 4 and 5 are missing. 



