I. INTRODUCTION. 



This publication is the Third, but an independent, Part of a monograph of 

 the Decapod Crustacea of that portion of the Oriental Region which lies within 

 the political boundaries of British India : it treats only of the prawns of the 

 maniple Peneus. 



The group, of which Peneus monodon Fabricius is the type, forms with the 

 genera Solenoceni Lucas, Parasolenocera "Wood-Mason, Peneopsis A. Milne 

 Edwards, PhUonicm Spence Bate, Halijjoras Spence Bate { = IIijriienopenens 

 S. I. Smith), Artemisia Spence Bate, and perhaps also Fimchalia Johnson, a 

 sub-family of the Peneidse. 



This sub-family {Peneinm) is distinguished from the two other sub-families 

 {Aristeinse and Sicijoninas) which constitute with it the family Peneidse, by 

 possessing, on the inner side of the basal joint of the antennular peduncle, a 

 large, twisted, setose plate that forms a sort of protection, on the inner side, 

 to the eye. 



Peneus differs from all the other genera of its sub-family (1) in having only 

 one gill-plume (artlirobranch) on the epimeral articulation of the penultimate 

 thoracic leg, and (2) in not having the cervical groove continued as a distinct 

 impression right across the dorsum of the carapace. 



For a statement of the views here adopted as to the relations of the family 

 Peneidse to the other families and sections of the suborder Macrura, I would 

 refer to pp. 8-11 of my Catalogue of Indian Deep Sea Crustacea Decapoda 

 Macrura and Anomala in the Indian Museum, and also to the tabular statement 

 on p. 15 of the first fascicle of the first part of this Catalogue, published 

 m 1901. 



The prawns of the Peneus group are found in the greatest abundance and 

 variety in the Indo-Pacific, from the Red Sea and east coast of Africa (as far 

 as 33° S.) to Japan and Australia. Eastwards of this centre they send oifshoots 

 (4 or 6 species) to the shox-es of California and Panama, and westwards they 

 occur in the Mediterranean (4 species) and its Atlantic gate (one of the Medi- 

 terranean species occasionally straggling into British waters), and all along the 

 Atlantic coasts of America from New England to Brazil (9 or 10 species), one 

 species ranging perhaps as far south as the northern end of Patagonia. 



The Penei are particularly fond of wai'm shallow seas, and in Indian limits 

 they swarm, both in their larval and in their adult stages, in muddy waters 



