326 Annah of the South African Museum. 



Remarks. This form was described by the present author in the 

 year 1909 from specimens collected in South Georgia. It is very 

 closely allied to the northern species M. hirsuticornis, Brady, though 

 differing in some particulars rather conspicuously, especially as 

 regards the size of the ocellus and its position in relation to the eye. 



Occurrence. The present form was reared in considerable numbers 

 from the mud kindly forwarded to me in 1909 by Dr. Purcell, and 

 taken in the neighbourhood of Bergvliet. 



Distribution. South Georgia, Falkland Islands, Australia. 



24. MACROTHRIX SPINOSA, King. 

 (Plate XXXVI, figs. 3, 3 a, 6.) 



Macrothrix spinosa, King. On Australian Entomostraca. Papers 

 and Proc. Roy. Soc., Van Diemen's Land, vol. ii, pt. 2, 1852, p. 256, 



pi. 6 E. 



Specific Characters Female. Carapace, seen laterally, broadly oval 

 in outline, and terminating behind in a well-marked though short 

 protuberance occurring about in the axis of the body ; dorsal margin 

 evenly curved, ventral slightly bulging in front of the middle. Head 

 of moderate size, with the rostral part comparatively less prominent 

 than in the preceding species, lower edge behind the rostrum straight. 

 Surface of shell sculptured, especially towards the dorsal face, with 

 closely set squamous ridges, giving the upper contours a more or less 

 conspicuous jagged appearance. Eye comparatively smaller than in 

 the preceding species ; ocellus extremely minute and located near the 

 end of the rostrum. Antennulae less strongly built than in the pre- 

 ceding species, with the spinules of the inner face shorter. Epipodite 

 of last pair of legs much larger than that of the anterior pairs, forming 

 an elliptical vesicle, generally covering laterally the end of the tail- 

 piece. The latter resembling in shape that in M. propinqua, but 

 comparatively shorter and more rounded at the end, with the anal 

 denticles fewer in number. 



Body rather pellucid with a faint yellowish tinge. 



Length of shell scarcely exceeding - 54 mm. 



Remarks. The present species was established as early as the year 

 1852 by King, and was redescribed by the present author in 1888 from 

 specimens raised out of dried Australian mud. It is easily distinguish- 

 able from the preceding species by its much smaller size and the 

 conspicuously squamous sculpture of the shell. The form described 

 by the present author from South America as M. squamosa is scaicely 

 different from this species. 



