12 2 



"In adult and subadult specimens of S. maxiimuu the eyes have the upper section sHghtly 

 or at most a little smaller than the lower; besides, the fourth and fifth abdominal segments 

 have no median dorsal tooth. In adult and subadult specimens of S. abbreviatum the eyes have 

 their upper section much smaller than the lower, and the fourth and fifth abdominal segments 

 each a conspicuous dorsal median tooth from the hind margin. In half-grown or still somewhat 

 smaller specimens of S. abbreviatum the abdominal armature mentioned is feebly developed, 

 and the upper section of the eyes is proportionately still smaller than in larger specimens; in 

 small specimens of S. maximuvi the eyes have their upper section somewhat smaller as compared 

 with the lower than in large specimens, but that section is yet conspicuously larger than in the 

 other species". 



As the material collected by the "Siboga" contains only a single adult specimen of 

 5. maxiimini and only immature specimens of S. abbreviatum a more detailed account is to 

 be postponed, but still a few differences between them may be mentioned. S. maximum is 

 conspicuously larger than 5. abbreviatum; the adult female captured by the "Siboga" measures 

 24 mm. in length, while the male from the North- Atlantic mentioned in the "Ingolf" Report is 

 '^x^. mm lono- fio- 6« shows the head and figs, be and 6c/ the left copulatory organ of the 

 latter specimen. The chela (fig. bb) of .S". maximum is shaped as in 5. abbreviatum, but it is 

 proportionately larger than in this species. Finally the copulatory organs. In 5'. maximum the 

 spine-shaped process is strongly bent before or at the middle (fig. 6d); the terminal process 

 is thick, decreasing somewhat in breadth from the base to near the middle, and then keeping 

 the same breadth to near the end, which is cut off obliquel)- and besides with a small or 

 inconspicuous tooth on the terminal margin, while the outer angle is triangularly produced and 

 terminates in an acute tip; the proximal process, which projects from the outer side of the 

 lobe at some distance from the terminal, is about as long as and somewhat less strong than 

 this process, while the lateral process, which is inserted on the inner margin of the median lobe 

 a little from its base, is somewhat short and much more slender than the proximal process. 

 In S. abbreviatum the terminal process is essentially as in .S. maximum, but tapering somewhat 

 in breadth to rather near the end which is distinctly bifid, while the proximal process is scarcely 

 one-third as thick as the terminal and slightly thicker than the lateral process; in other respects 

 all processes in 5. abbreviatum are about as in S. maxiuium, but the great difference in the 

 thickness of the proximal process is evidently an excellent specific character. 



Distribution. — Of 5. maximum I have seen specimens from the Pacific, and in the 

 Atlantic it goes as far northwards as lat. 6i°49'N., where it was captured by the "Thor". 



25. Stylocheiron abbreviatum G. O. Sars. 



1883. Stylocheiron abbrevmtum G. O. Sars, Forh. Vid. Selsk. Christiania for 1883, N» 7, p. 33. 

 1885. Stylocheiron abbrevmtum G. O. Sars, Challenger Rep. Vol. XIII, p. 147, PI. XXVII, 



figs. II — 13. 

 1896. Stylocheiron chelifer Chun, Bibl. Zool. Heft. 19, p. 162, Taf. XI, Fig. 1—8. 



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

 to surface, i young specimen. 



