r>lG Dr. A. Alcock — A Revision 



sulcus defined ventrally only, by tlie buttress of the post- 

 antennular (antennal) spine, 



Antennular flagella short. The first pair of thoracic legs 

 may, in the adult male, be enormously elongate, especially 

 as to the propodite ; but in the female, and, as Nobili has 

 shown, in certain adult males, may be of the oixlinary Peneus 

 form. Exopodites are present on all the thoracic legs. 



According to Nobili, epipodites are present on all but the 

 last two thoracic appendages, and pleurobranchiae on the six 

 posterior thoracic somites. 



Andricum symmetrical, simple, much as in Peneus (s. r.). 



According to Nobili, the branchial formula is the same as 

 that of Peneus (s. r.). 



Only the following species is known : — 



Ileteropeneus longimanus, cle Man, he. cit.; see also Nobili, loc. cit. — 

 Java Sea ; Singapore. 



3. Metapeneus, Wood-Mason. 



Metapeneus, Wood-Mason, Ann. & Mag. Nat. Tlist. (0) viii. 1891, 

 p. 271. 



Type, M. affinis, Edw. 



Rostrum toothed on its dorsal edge only. Antero-inferior 

 angles of carapace either rounded or spiniform. Post- 

 antennular sulcus defined only ventrally by the buttress of 

 the postantennular (antennal) spine. No longitudinal or 

 transverse sutures on the carapace. 



Antennular flagella short or of moderate length. Endo- 

 podite of maxilhdes (first maxillae) somewhat abbreviated, 

 two-jointed. Exopodites present on all or all but the last 

 pair of thoracic legs. 



Epipodites absent from the third maxillipeds as well as 

 from the last two thoracic appendages. No pleurobranch on 

 the last thoracic somite. 



Andricum complicated, symmetrical or asymmetrical: if 

 symmetrical its distal angles are more or less spout-like; if 

 asymmetrical one lobe is either larger or longer than the 

 other, and both are split up into interleaved convoluted 

 lobules. 



The third maxillipeds never exhibit secondary sexual 

 characters in the male, but the last pair of thoracic legs 

 sometimes do. 



The branchial formula is : — 



