The Fresh-water Entomostraca of Cape Province. 32 > 



GEN. 7. MACEOTHRIX, Baird. 



Remarks. In the restriction here adopted, the present genus may 

 be easily distinguished from the preceding one, to which it bears a 

 close relationship, by the somewhat different shape of the head, the 

 rostral part of which is more prominent, and wholly wants the charac- 

 teristic arched crests in front, present in all the species of Echinisca. 

 Moreover, the coarser structure of the autenuulae and their pronounced 

 curvature is rather characteristic, as also the short and stout shape of 

 the tail-piece. Several species of this genus have been discovered 

 from different parts of the world ; but, as above stated, some of these 

 ought to be transferred to the preceding genus. Two well-defined 

 species belong to the fauna of Cape Colony and will be described 

 below. 



23. MACROTHRIX PROPINQUA, G-. O. Sars. 

 (Plate XXXVI, figs. 2, 2 a-c.) 



Macrothrix propingua, G. O. Sars. Fresh-water Entomostraca from 

 South Georgia. Arch. f. Math. u. Naturv. 1909, p. 5, pi. 1. 



Specific Characters Female. Carapace, seen laterally, oval in out- 

 line, terminating behind in a short and obtuse protuberance occurring 

 about in the axis of the body ; dorsal margin more or less strongly 

 arched and quite smooth, lower edges of valves only slightly curved 

 and exhibiting the usual armature of strong spiniform setae. Head 

 not defined above by any distinct depression from the carapace, and 

 having the dorsal margin evenly curved throughout ; rostral part 

 rather prominent and without any trace of lateral crests, lower edge 

 of head behind the rostrum straight. Surface of shell nearly smooth. 

 Eye comparatively large ; ocellus much smaller and located nearer to 

 the tip of the rostrum than to the eye. Autenuulae rather strongly 

 built and considerably curved, gradually dilated distally, with about 

 six transverse rows of delicate spinules inside, projecting from as many 

 notches of the anterior edge. Antennae of the usual structure. Epi- 

 podite of last pair of legs scarcely larger than those on the other legs. 

 Tail-piece short and stout, obtusely truncated at the end, with the 

 hind edge distinctly siuuated immediately above the anal fissure, anal 

 denticles about ten on each side, apical claws very small, upper part of 

 posterior edge slightly arched and finely denticulate throughout. 



Body semipellucid, with a more or less distinct reddish-orange 

 tinge. 



Length of shell reaching 0'93 mm. 



