85 



behind its acute end bent conspicuously outwards. The median lobe with nearly its basal half 

 broad, its distal half much more slender and terminating in a less or more produced triangle 

 with the end somewhat blunt; the lateral process, which is inserted at the end of the broad 

 part, is a little or scarcely shorter than the distal part, thick at the base, then nearly suddenly 

 much narrowed and towards the acute end much curved ; the additional process is long and 

 strong, much overreaching the lobe, much curved, acute. The setiferous lobe slightly over- 

 reaching the median, broad, with the protuberance very developed, and the outer margin with 

 setie to near the stalk. It may be added that the organs of specimens from the Atlantic and 

 the Pacific agree well with my figures, and that the absence of the spine-shaped process is at 

 least a rare feature within the genus Thysanopoda. 



Young Specimens. — In specimens less than half-grown the rostral plate is longer, 

 forming a broad triangle with the sides convex and the acute end slightly produced, while the 

 lamella from first antennular joint is somewhat smaller and has not yet fully attained it final 

 characteristic shape. 



Distribution. — The species is common in the eastern part of the Atlantic from 

 lat. 36°i7'N. to 28° N. (H. J. Hansen) and is known from the Pacific (see above p. 81). 



4. Thysanopoda orientalis n. sp. PI. XIII, figs. 2a — 2/. 



Stat. 128. July 22. Lat. 4° 27' N., long. 125° 25'./ E. 1645 m. Hensen vertical net, from 700 m. 



to surface, i very young specimen. 

 Stat. 143. August 7. Lat. i°4'.5 S., long. I27°52'.6E. 1454 m. Hensen vertical net, from 



1000 m. to surface. 2 very small specimens and 2 larva;. 

 Stat. 185. September 12. Lat. 3°2oS., long. I27°22'.9E. Manipa-strait. Hensen vertical net, 



from 1536 m. to surface, i immature male. 

 Stat. 203. September 19. Lat. 3°32'.5 S., long. 124° 1 5'.$ E. Hensen vertical net, from 1500 m. 



to surface, i very large female. 



Description. — This species is not only similar to the two closely allied species 

 T. aaitifrons Holt & Tatt. and 

 T. inicrophthalina G. O. Sars 

 {= T. distingiienda H. J. H.), 

 but even intermediate between 

 them as to size and antennular 

 lobe, while the copulatory organs 

 show that the three species are 

 well founded. (In Bull. Mus. 

 Ocean. Monaco, N° 42, I des- 

 cribed T. acutifrons and T. 

 distinguenda, and later Holt & 

 Tattersalt dealt with them 

 asrain and added grood fig-ures ; 

 the reader is referred to both 

 papers). In T. orientalis the body is larger and especially the cephalothorax is conspicuously 



T. acutifrons 

 Monaco Stat. 1639. 



T. inicrophthalina G. O. S. 



= T. distingticnda H. J. H. 



Monaco Stat. 1749. 



T. orientalis n. sp. 

 Agassiz Stat. 4721. 



