22 



New Caledonia, whence it has been recorded by the French author. As the latter figured all 

 the details accurately, it is needless to enter into a fresh description. According to Milne-Edwards 

 the species grows to a very large size (breadth of carapace 26 mm., total breadth of animal 

 across expanded legs 116 mm.); my specimens were considerably smaller. 



4. Elamena truncata (Stimpson). PI. 1, Fig. 4. 



1858. Trigonoplax truncata Stimpson. Proc. Ac. Nat. Sc. Philadelphia, 1858, p. 109. 

 1873. Elamene truncata ') A. Milne-Edwards. Nouv. Arch. Mus. Paris, t. 9, p. 323. 

 1893. Elamene truncata Henderson. Transact. Linn. Soc. London (2) v. 5, p. 395. 

 1900. Elamene truncata Borradaile. Proc. Zool. Soc. London, 1900, p. 575. 

 1900. Elamena truncata Alcock. Journ. As. Soc. Bengal, v. 69, prt 2, p. 386. 



1905. Elamene truncata Lenz. Abhandl. Senckenb. Gesellsch., Bd 27, p. 367, pi. 48, f. 15 — 15a. 



1906. Elamene truncata Baker. Transact. Proc. R. Soc. South Australia, v. 30, p. 112, pi. 2, f. 2. 



1906. Elamena truncata Laurie. Rep. Pearl Oyster Fish. Ceylon, prt 5, p. 428. 



1907. Trigonoplax truncata Stimpson. Smithson. Inst., Miscell. Coll. v. 49, p. 146. 



Stat. 172. Gisser, east of Ceram. On coral reef. 2 egg-bearing 9- 

 Stat. 181. Ambon. On coral reef. 2 <ƒ, 2 egg-bearing 9- 



Lenz mentions' the variation of the carapace, even among individuals of the same sex. 

 In my specimens, the 4 9 have the carapace more distinctly angular than the cf, especially in 

 the case of the 9 from Gisser (cf. fig. 4 and 4^); the posterior angle is here prominent and 

 hooked, the anterior at least indicated. Besides, the walking legs of the 9 are much shorter, 

 scarcely i 1 /,, times the breadth of the carapace; in the d* they are more than twice this 

 breadth. Only the smallest 9 from Ambon has the legs relatively as much elongate as 

 the cf and the dactyli are as long, and nearly straight, as in the latter sex. Thirdly, the 

 corneae of the eyes project beyond the carapace in the cf, but are not visible from above in 

 the other sex. 



The truncation of the carapace is different and apparently independent from the sex. 

 Both Lenz and Laurie allude to this, and the former has figured the difference in his two 

 speGJmens. The anterior border may be either somewhat produced in the middle, or quite 

 straight, or even slightly concave, and both angles may be prominent; yet in all cases there 

 is no doubt about its truncation. 



The carapace is very thin, lamellar, with scarcely any indication of regions, smooth and 

 naked; the border projects as a sharp rim horizontally. The antennae, the second peduncle- 

 joint of which is the longest, arise beneath the eye-stalks and are not much shorter than the 

 antennules, that are folded up beneath the lamellar front and separated by a very 

 marked, thick and high septum, extending forward up to the anterior 

 border of the rostrum (fig. 4a). Epistome short, though distinct, deeply sunk. There are 

 no proper orbits, but the eye leans against a very small postocular tooth, the existence of 

 which is denied by Alcock. On the pterygostomial regions is a very prominent, waved, sharp 



I) Milne-Edwards described it as a new species, apparently in ignorance of Stimpson's diagnosis; it is remarkable, that he 

 chose the same specific name as his predecessor. Most subsequent authors regard Milne-Iïdwards as the original describer. 



22 



