£ 



466 



Memoirs of the Indian Museum. 



[Vol. V, 



Fig. io. — Ligia exotica, maxilliped, 

 seen from inner or anterior side. 



the Lake Chilka specimens of L. exotica and also in Honolulu specimens of this 

 species in my collection , it does not appear to apply to all the species of the genus ; 



thus, in L. oceanica, according to Sars (1898, p. 156), 

 the si de- plates are denned "from the corresponding 

 segments by a slight groove." This is certainly the 

 case in the specimens of this species that I have been 

 able to examine, but unfortunately there is no oviger- 

 ous female among them, though I presume Sars' des- 

 cription applies to both sexes. In speaking of L. 

 exotica, Miss Richardson (1905, p. 677) says, the epi- 

 mera are " not distinctly separated off from the dorsal 

 portion of the segment, only a faint line, almost in- 

 conspicuous, indicates the place where the coalescence 

 has taken place ' ' ; she makes no mention of sexual 

 differences in this point, though, as I have said, in 

 ovigerous females from Lake Chilka and from Hono-' 

 lulu, there is a distinct suture in segments 2, 3 and 4. 

 For L. baudiniana, Miss Richardson (1905, p. 679) 

 says, "the epimera are coalesced with the segments, 

 faint depressed lines indicating the place of the 

 union" , and she gives a similar description for L. occidentalis (p. 682), while in 

 L. pallasii, she says, "the epimera of all the segments are broad plates, occupying 

 the whole of the lateral margins of the segments and indicated by distinct lines ' 

 (p. 683), though in L. olfersii "there is not even any trace, such as a faint line 

 to mark the place where coalescence has taken place " (p. 675). In L. novae-zealan- 

 diae y Dana, the side-plates in the male are all united with their segments, the union 

 being indicated at most by a faint line ; in the female the side-plates of segments 

 2, 3 and 4 are separated from the segments by a fairly distinct suture and, in most 

 cases, there is on segment 5 a distinct groove corresponding to the suture in the 

 preceding segment. There seems to be also the same want of uniformity in this 

 character in Deto : for, while in D. aucklandiae there is the same difference be- 

 tween the sexes as in Ligia exotica, in the other species of Deto, the side-plates are 

 continuous with the segments, and the junction of the epimera is not marked 

 by a distinct groove or suture. In this connection it should be remarked that 

 Dollfus (1893C, p. 343) established the genus Geoligia, chiefly on the character 

 that all the side-plates were continuous with their segments. Although it is evident 

 that this character in itself is not sufficient to distinguish the genus Geoligia from 

 Ligia, the only species of that genus. at present known are truly terrestrial, living far 

 away from the sea, and in Geoligia perkinsii, Dollfus (1900, p. 525), the uropoda have 

 the branches articulated into several joints instead of being undivided as in Ligia. 



The whole dorsal surface of the segments of the peraeon is covered with numer- 

 ous small granulations, some of which seem to be almost acute posteriorly ; they are 

 scattered irregularly over the segments without forming any definite rows. In the 



