South African Crustacea. 



distal tooth of the outer margin of the outer ramus. The 

 apical breadth of the telson is a fourth of its length, as 

 measured between the distal points of the lateral margins, 

 beyond which it extends in a shallow three-sided convexity, 

 bordered with plumose setae two central spines and a small 

 and large pair at the corners. Between the mouth-organs of 

 this and the preceding species there are several small differ- 

 ences of detail. 



Total length of specimen 22 mm., the carapace 7 mm., the 

 telson 3 mm. 



Locality. Delagoa Bay, where the specimen was obtained 

 by Mr. K. H. Barnard. A 2123. 



ALPHEUS DISSODONTONOTUS, n. sp. 

 Plate LXXXVI. 



This striking species is closely allied to Alplieus praedator, 

 de Man, 1908, and to A. bidens (Olivier), as recently described and 

 figured by de Man, who finds a synonym of it in A. tridentatus, 

 Zehntner (Eevue Suisse Zool., vol. 2, p. 204, pi. 8, fig. 24, 1894). 

 The remarkable feature of these rare forms is the presence of two 

 strong teeth on the back of the carapace, not beside the rostral tooth, 

 but well to the rear of it. To this feature the new specific name 

 refers, in agreement with Olivier's bidens, while the addition of the 

 rostral tooth would justify the epithet tridentatus. In the two earlier 

 species the rnedio-dorsal carina is interrupted behind the dorsal teeth 

 and resumed with an obtuse tubercle. In the new species this 

 tubercle is not found, and the dorsal teeth are separated from the 

 carina by a very narrow groove. The most obvious further distinction 

 is in the second peraeopods, in which the first carpal joint is decidedly 

 longer than the second, instead of shorter as in the other two species. 

 The telson is just twice as long as its greatest breadth at the base ; 

 the apical curve is closely fringed with 24 strongly plumose setae 

 and numerous short spines, with a very small pair at the outer 

 corners and a rather larger pair just within this small pair. The 

 upper dorsal pair of spines is a little above, and the lower pair a 

 little below the middle of the telson. 



The globular eyes are clearly visible beneath the inflated hoods ; 

 as to the latter de Man says that in A. praedator " the eye-hoods end 

 anteriorly in an obtuse tubercle " ; in the present species it is the 

 eyes themselves that show a small tubercle which seems to project 

 clear of the hoods. The first antennae have a broad stylocerite, the 



