1907.] CRUSTACEA OF THE THIRD TANGANYIKA EXPEDITION. 271 



Platythelphusa maculata (Cnnnington). (Plate XYII. 

 figs. 5 & 6.) 



Limnothelphicsa maculata Cunnington, Proc. Zool. See. 1899, 

 p. 698. 



Limnothelphusa maculata Moore, ' The Tanganyika Problem ' 

 (London, 1903), p. 280. 



Limnothelphusa maculata Rathbun, Nouv. Arch. Mus. Hist. 

 Nat. Paris, 4*^ ser., vii. (1905) p. 269. 



As this species is now regarded as falling under the genus 

 Platythelphusa, in consequence of the examination of much more 

 extensive material, it becomes evident that it merits a more 

 complete specific description, which accordingly follows. 



DescrijJtion. — Carapace moderately convex, extending laterally 

 less than an orbit's breadth beyond the external orbital angle. 

 Antero-lateral margins shorter than postero-lateral, with which 

 they are almost directly continuous. Number of spines on antero- 

 lateral margin variable, usually three, in addition to the spine at 

 the external orbital angle. Regions and sutures moderately 

 marked. Postero-lateral regions exhibit a series of small slightly 

 oblique granular ridges. Front more than one-third the width of 

 the carapace, margin perlated, and in extreme cases produced into 

 a small spine at each extremity. Sub-orbital spines little deve- 

 loped : no spine on the descending process of the fi'ont. Orbits 

 large, '24 width of carapace ; orbital margins perlated. Eyes and 

 peduncles large. Chelipeds in the male unequal, subequal in the 

 female ; merus rather short, trigonous, with distally a sharp spine 

 on the anterior margin ; carpus with two spines on inner margin 

 and one above the point of articulation with the hand. Fingers 

 of the larger chela gape considerably, are pointed and slightly 

 hooked, and cany a few larger crushing-teeth pi-oximally, with 

 smaller teeth distally. Fingers of the small chela, and both chelse 

 of the female (Plate XVII. fig. 5), distally meet closely in a sharp 

 cutting-edge, while proximally there are uniform teeth of moderate 

 size. Ambulatory legs of moderate length. Colour in life dark 

 brownish grey, with dark brown or reddish spots. 



As now there has been obtained quite an extensive sei-ies of 

 specimens, some of which are larger than those examined before, 

 it seems worth while to furnish a further list of dimensions, to 

 compare with those given under the original description of this 

 species. As in the case of P. armata, the larger chela of old 

 male specimens is of a great size, the length of hand and pollex 

 exceeding the total breadth of the carapace. 



Adult male : mm. 



Length of carapace 12*9 



Breadth of carapace 1 6"4 



Fronto-orbital width 13-2 



Width of front 6-1 



Larger chela: greatest length of hand and pollex 16*9 



„ ,, greatest height of hand 8-7 



19* 



