BY WILLIAM A. HASWELL, M.A., B.SC. 99 



Lysianassa australiensis, (Plate XII., figs. 3 and 4) on the other 

 hand, has the anterioi* gnathopoda non-prehensile ; while the telson 

 is divided to the base. It is to be distinguished from A. Kroyeri 

 chietly by the form of the terminal joints of the posterior gnathopod, 

 as well as by the non-prehensile anterior gnathopods. The follow- 

 ing is a more detailed description of L. australiensis : — 



The eyes are reniform, rather large, but not nearly meeting above. 

 The fourth segment of the pleon has a depression on its dorsal 

 aspect. The superior antennae are about equal in length to the 

 head and the first segment ; the first joint thick, slightly convex 

 on its dorsal border, scarcely projecting beyond the angular process 

 of the head ; the second and third segments are very short; the 

 flagellum is scarcely longer than the peduncle, of ten articuli, the 

 appendage with five or six. The inferior antennae are of the same 

 length as the superior, much slenderer : the flagellum and peduncle 

 are of nearly equal length, the former with ten joints. The first 

 pair of gnathopods are obscurely sub-cheliform, the propus having 

 at its distal end an obscure lobe armed with a pair of stout spines 

 against which the dactylus works. The posterior gnathopods are 

 characterised by the extreme smallness of the dactylus, which is 

 nearly terminal and is ornamented, together with the apposed 

 palmar border, with some minute cilia : the ventral border of the 

 propus is ox^namented with a row of short setae and the distal 

 border with a fasciculus of more slender hairs. The telson is cleft 

 to the base ; each of the halves is ornamented with three short 

 conical spines. 



The above description would apply equally well to L. nitens, as 

 far as the antennae, anterior gnathopoda and telson are concerned, 

 except that the flagellum of the superior pair is a little shorter in 

 the latter species. The main diflference between the two species 

 lies in the posterior gnathopoda, whicli in L. nitens have a concave 

 terminal palm with a well developed dactylus. 



L. affinis (pi. XII., figs. 5 and 6) differs from both of these in 

 the size of the eyes, which nearly meet above, and in the great 

 length of the inferior antennae. The segments of the flagellum of 



