COLLECTED IN CEYLON. 295 



posterior antennae large, but not so excessively thick and mus- 

 cular as in I. sordidus. Postabdomen consisting of two laminae, 

 each of which bears a long, slender, terminal claw, and behind 

 this a series of twelve marginal curved spines, six long and six 

 short alternately ; following close upon these, and immediately 

 behind the anal orifice, is another series of about twelve equal, 

 but still shorter, spines, then a sinus corresponding with the 

 intestinal outlet ; between this and the anterior angle of the limb 

 is another row of six larger and more widely separated spines, 

 followed by a couple of long slender setae. The carapace is 

 marked within the posterior and ventral margins by several con- 

 centric lines, probably corresponding with periods of growth, 

 and perhaps indicating also that the shell of this species does 

 not undergo the normal periodical exuviation ; the posterior 

 and ventral margins of the carapace are densely fringed with 

 plumose hairs, long on the ventral, but becoming gradually 

 shorter towards the dorsal margin. The four-jointed branch of 

 the large antenna has imperfectly marked divisions in the centre 

 of each joint (fig. 7), giving it the appearance, under a low 

 power, of being divided into eight joints. Length ^ of an 

 inch ('98 millim.). 



G-enus Maceotheix, Baird. 



Maceotheix TEiSEEiALis^n. sp. (Plate XXXVII. figs. 16-20.) 

 The carapace seen laterally is subtriangular or heart-shaped, 

 the posterior extremity tapered, angular and mucronate ; the 

 head is slightly produced into a triangular rostrum, from which 

 depends the strap-like anterior antenna, serrated on its anterior 

 margin and ending in three small setae. The free margins of the 

 carapace are serrated with short stout teeth, which run more or 

 less distinctly in series of three (fig. 20), the intervals bearing 

 long slender hairs. Length -^ of an inch (1*05 millim.). 



Family Lync^idjE. 

 Genus Alona, Baird. 



Alona acanthoceecoides {Fischer). (Plate XXXVIII. fig. 1.) 

 Lynceus acanthocercoides, Fischer, Leydig, Norman, and Brady. 

 Eurycercus acanthocercoides, Schodler. 

 Alona acanthocercoides, P. E. Miiller. 

 Leydigia acanthocercoides, Kurz, Herrick, 



