18 



n. Telsoii with lateral marginal spines at its distal end : — 



1. No exopodite to last paii- of thoracic legs : no branchiostegal 



spine at antero-inferior angles of carapace ... ... M. ends. 



2. Last pair of thoracic legs with exopodite : a branchiostegal spine : 



no notch and spine on merus of last pair of thoracic legs of 

 male : — 



i. Inner antenuular flagellum much longer than outer, — 

 as long as its peduncle : — 



a. Median limb of thelycum a short ridge ... M. coniger. -Ipf""'' 'r 



b. Median limb of thelycum a broad, undermined 



plate, with its free (posterior) edge recurv- 

 ed and bilobed ... ... ... M. andamaneyisis. 



ii. Antennular flagella ecjual, — about one-third the 

 length of the peduncle : — 



a. A stridulating organ on each side of the 



carapace, playing against the free edge of 



the 1st abdominal tergum ... ... J/, stridulans. 



b. No stridulating organs on cai'apace ... M. niogiensu: 



. 1. Metapeneds monoceros, Fabr. Plate III., fig. 7, 7 a-c. 



Penseus 7no7ioceros, Fabrioias, Entomol. Syat., Suppl., p. 409, 1798: ?(Bosc, Latreille) : Millie Edwarde, 

 Hist. Nat. Cmst., II. p. 415, 1837: ? Dana, U.S. Expl. Exp. Crast. pt. I. p. 605, pi. xl. tig. 5, 1852 : Stimpeou, 

 Proo. Acad.Philad. 1860, p. 41 (part.)-. Miers, P.Z.S., 1878. p. 301 : Hilgendorf, MB. Ak. Berl. 1878, p. 844: 

 Spence Bate, Ann. Mag. Nat. Hist. (5) VIII. 1881, p. 177, pi. xi. fig. 2 : Haswell, Cat. Austral Crust., 1882, p. 200 : 

 Ortmaun,Zool. Jahrb., Sysb., V. 1890, p. 450, (part.) pi. xxxvi. fig. 3b. (not 3a): Thallwitz, Abh. u. Ber. JIns. 

 Dresden, 1890-91, No. 3, p. 2 : de Man in Weber's Zool. Ergebn. Niederl. Oat-Ind. II. 1892, p. 513, fig. 54, and 

 Zool. Jahrb., Syst., X. 1898, p. 680 : Doflein, Abh, bayer Akad, Miinchen 1902, p. 631. 



Metapenieus monoceros, Nobili, Boll. Mug. Torino, XVIII. 1903. No. 452, p. 3, and No. 455, p. 3. 



Penaeus incisipes, Kishinonye, Journ. Fish. Bur., Tokyo, VIII. i. 1900, p. 18, pi, iv. fig. 2. pi. vii. fig. 0, (w 

 (nee Bate). 



Body covered with a harsh and very short tomentum. 



Rostrum nearly straight, uj^tilted, reaching nearly to, or a little beyond, 

 the tip of the antennular peduncle ; armed dorsally with 9 — 12 teeth, which do 

 not form much of a crest. Post-rostral crest continued to, or almost to, the 

 posterior border of the carapace. 



Antero-lateral angles of carapace broadly rounded off. A very small post- 

 ocular (orbital) tooth. Post-antennular (antennal) spine strong, produced as a 

 salient ridge to the base of the small hepatic spine, the ridge bounding a well 

 marked post-antennular groove wdiich meets the cervical groove. Gastric 

 region defined anteriorly, on either side of the rostrum, by a short obhque post- 

 orbital groove. Branchial region defined (1) anteriorly, by a deep and narrow 

 crescentic groove (anterior part of cervical groove) which embraces the base of 

 the post-antennular ridge and meets the post-antennular groove, and (2) super- 

 iorly, by a sinuous ridge — most distinct in its posterior half — which runs from 

 the hepatic spine almost to the posterior border of the carapace. 



The 2nd — 6th abdominal terga, usuahy the 1st also, are carinated 



