82 



perceive that the two specimens belonged to different species, though he states that Mr. Lumholtz' 

 specimen possesses a "very small dentiform projection" from the hind margin of third abdominal 

 segment, while the "caudal segments in the Challenger specimen would appear to be quite 

 smooth above". The Lumholtz' specimen is certainly T. monacantha Ortm., as this species 

 agrees with Sars' description in the structure of the antennulse and in the presence of a tooth 

 on the lower margin of the carapace and the abdominal denticle mentioned. The "Challenger" 

 specimen agrees exactly with my description (in Buil. Mus. Oc. Monaco, N n 30 & 42) of T. 

 distingncnda H. J. H., and the latter name must therefore be cancelled as a synonym. 



According to my study of a vast material of this genus the following species have been 

 established : T. tricuspidata M.-Edw., T. cristata G. O. S. (= T. biprodncta Ortm.), T. Agassizii 

 Ortm., T. monacantha Ortm. (= T. ctcnophora Illig, and T. lateralis H. J. H. 1 )), T. obtusifrons 

 G. O. S. (= T. valgaris H. J. H.), T. crqttalis H. J. H., T. pectinata Ortm., T. microphthalma 

 G. O. S. (= T. distinguenda H. J. H.), T. acutifrons Holt & Tatt., T. cornuta Illig (= T. 

 insignis H. J. H. 2 )), T. egregia H. J. H. and T. megalops Illig. The "Siboga" collection contains 

 specimens of 3 of these 1 2 species, to which I add a new species, T. oricntalis. 



2. Thysanopoda tricuspidata H. M.-Edw. PI. XII, figs. 3a — $0. 



1S30. Thysanopode tricuspide H. Milne-Edwards, Arm. Sc. Nat. T. XIX, p. 454, PI. 19. 

 1837. Thysanopoda tricuspida H. Milne-Edwards, Hist. Nat. Crust. T. II, p. 466, PI. 26, figs. 1 — 6. 

 1885. Thysanopoda tricuspidata G. O. Sars, Challenger Rep. Vol. XIII, p. 98, PI. XVII, and 

 p. 165, PI. XXXI, figs. 1 — 22 (larval stages). 



Stat. 37. March 30/31. Sailus ketjil, Paternoster-islands. 37 m. Surface. 4 specimens: 2 larva; 



and 2 very young. 

 Stat. 40. April 2. Anchorage off" Pulu Kawassang, Paternoster-islands. 12 m. Townet. 1 larva. 

 Stat. 66. May 7/8. Bank between islands of Bahuluwang and Tambolungan, south of Saleyer. 



8 — 10 m. Plankton. 23 specimens, in various stages from larger larvae to half-grown 



individuals. 

 Stat. 75. June 8. Lat. 4°S7'.4S., long. H9°2'.8E. 18 m. HENSEN vertical net, from 11 m. to 



surface, electric light in net. 3 larva;. 

 Stat. 96. June 27. South-east side of Pearl-bank, Sulu-Archipelago. 15 m. Surface. 1 very 



young specimen. 

 Stat. 99. June 28/29/30. Lat. 6°7'.5 N., long. I20°2Ó'E. Anchorage off" North-Ubian. 15 — 23 m. 



Surface. 1 very young specimen. 

 Stat. 106. July 4. Anchorage off Kapul-island, Sulu-Archipelago. 13111. Townet. 4 specimens, 



from very small to half-grown. 

 Stat. 117'. July 12. Lat. i°i5'N., long. 123° 37' E. Plankton, townet. 3 larva;. 

 Stat. 125. July 18/19. Anchorage off Sawan, Siau-island. 27 m. Townet. 1 larva. 

 Stat. 128. July 22. Lat.4°27'N., long. I25°25'.7E. 1645 m. HENSEN vertical net, from 700 m. 



to surface. 1 very young specimen. 

 Stat. 129. July 22/23. Anchorage off Kawio- and Kamboling-islands, Karkaralong-group. 



23 — 31 m. Townet. 4 larvae. 

 Stat. 132. July 25. Lat. 5°56'.7N., I2Ó°25'E. 3302111. Plankton. 15 specimens, most of them 



mere larva;, the others very young. 



1) I had overlooked the pair of tiny denticles on the lower margin of the scutum, and Ortmann's description of the scutum 

 and the antennular armature in his T. monacantha is rather poor. 



2) Iixig's paper containing the description of his T. cornuta was published two or three days before the Monaco-paper, in 

 which I established T. i/isi^/iis. 



