520 Dr. A. Alcock — A Revision 



The third roaxillipeds and last pair of thoracic legs are not 

 known to show any modifications in the male. 



The branchial fornnila is the same as that of Metapeneus, 

 but the rudimentary arthrobrauch of somite YII. (second 

 maxillipeds) seems \o be absent, and there is no vestigial 

 filament, representing an anterior arthrobranch, on the 

 penultimate thoracic somite. 



In addition to the Indian species I have examined specimens 

 of P. membranaceus and P. serratus. 



List of the Species o/Parapexeus, S. I. Smith [sensu restricto). 



I. Telson lo'tth a single pair of lateral marginal spi?ies, which are fixed ; 

 carapace with a fine longitudinal fissure, extending on either side from 

 the orbital to the posterior border ; tip of adult andricmn cut up into 

 spines or hooks and lobules or filaments. 



1. Parapenens membranaceus (Risso), Heller, Crust, siidl. Europa, p. 296, 



pi. X. fig. 11. ( = P. longirostris, Lucas, Hist. Nat. Aniui. Artie, in 

 Expl. Sci. Algeria, Zool. i. pt. 1, p. 46, pi. iv. fig. Q, = P. Bocagei, 

 Johnson, P. Z. S. 18G3, p. 255, and 1867, p. 900.)— Mediterranean 

 and its western approaches. 



2. Parapenens politus, S. I. Smith, Proc. U.S. Nat. Mus. iii. 1881, p. 144. 



— N. Atlantic coast of U.S. America. 



3. Parapenens megalops, S. I. Smith, Proc. U.S. Nat. Mus. viii. 1885, 



p. 172. — "NV. Indies and neighbourhood, 155-288 fathoms. 



4. Parapeneus fissurus (Spence Bate), 'Challenger' Macrura, p. 263, 



pi. xxx\i. fig. 1. — Bay of Bengal to S. Pacific, up to 115 fathoms. 



5. Parapeneus investigatoris, Alcock & Anderson, Ann. & Mag. Nat. 



Hist. (7) iii. 1899, p. 279.— Gulf of Manar, Bay of Bengal, Anda- 

 man Sea, up to 419 fathoms. 



6. Parapeneus americanus, Rathbun, Bull. U.S. Fish. Comm. for 1900 



(1901) p. 102. (" May prove to be a subspecies of P. investi- 

 gatoris:')— Poxio Rico* 220-225 fathoms. 



7. Parapeneus longipes, Alcock, ?'?i/r«.— Coasts of India and Ceylon, 



7^-68 fathoms. Distinguished by the absence of a branchiostegal 

 spine. 



li. Telson ivith 2 or 3 2JCiirs of articulating marginal spinelets, in additio7i 

 to the fixed pair; carapace without longitudinal sutures; adult 

 petasma simple, open-pod-shaped. 



8. Parapeneus reciacutus (Spence Bate), ' Challenger ' Macrura, p. 266, 



pi. xxxvi. fig. 2. — Fiji, Philippines, Andamans, Bav of Bengal, 

 95-418 fathoms. 



9. Parapeneus serratus (Spence Bate), op. cit. p. 208, pi. xxxvii. fig. 1. — 



Fiji, 315 fathoms ; Torres Strait, 1400 fathoms. 



5. Parapeneopsis, Wood-Mason, MS. 

 Parupeneopsis, Alcock, Cat. Indian Deep-sea Crust. 1901, p. 14. 



Type, P. stylifera, Edw. 



Rostrum toothed dorsally only. Autero-inferior angles of 

 carapace sharp or dentiform. Postantennular sulcus defined 



