such as those into which the numerous deltas of the Bay of Bengal discharge. 

 Some of the smaller and harder-shelled species, however, like Metapeneus 

 sfridulans and mogiensis and Trachypenevs asper, are often found in clear water 

 on a bottom of coral- shingle, dead shells, etc. ; while a few thin-shelled species, 

 such as Metapeveiis coniger and several of the species of Farapeneus, belong to 

 the necton, and are only taken in deep water. 



Like most other Malacostraca the Penei are scavengers; but many are 

 carnivorous in a better sense, and several species prey upon marine larvee and 

 microscopic algae. 



As a rule the female is larger than the male and has a longer rostrum, the 

 latter being a persistent juvenile character. On the other hand, the male not 

 seldom differs from the female, either in the form of the terminal joints of the 

 third maxillipeds, or in the sculpture of the basal joints of the last pair of 

 thoracic legs. 



Penei, both as larvae and as adults, form the food of many fishes. Beyond 

 this, they in themselves constitute a not inconsiderable part of that plenteous 

 harvest of the sea which in this country still runs to waste for want of capital 

 and enterprise. What the prawn-fisheries of India might be worth it is difficult 

 to say ; but a statement published by Kishinouye, in the Journal of the Fisheries 

 Bureau of Tokyo for the year 1900, that the dried prawns annually exported 

 from Japan into China are valued at 200,000 yen (or a httle over £20,000), 

 shows that there must be possibilities in them. 



In conclusion, a word may be said upon the subject of "genus and species- 

 making." 



In splitting the group into geneea, scrutiny has been directed to the 

 following points : — 



(1) The fissures and sutures of the carapace: 



(2) The rostrum: whether serrated dorsally and ventrally, or only dor- 

 sally : 



(3) The endopodite of the maxUlules: whether segmented or not: 



(4)) The presence or absence of exopodites on the thoracic legs : 



(5) The number and distribution of the epipodites and branchite. 



As regards species, characters founded on the length and dorsal armature 

 of the rostrum tend to mislead ; for not only is this part of the body variable 

 in itself and liable to malformation, but it also often exhibits sexual differences, 

 and changes its proportions during growth, in the same species. 



On the other hand, the details of sculpture of the carapace are specifically 

 constant, irrespective of sex and age; and the relative length of the sixth 

 abdominal somite, and the relative length of the telson and the state of its 



