EEPORT ON THE PYCNOGONIDA. 63 



The last four joints describe a spiral curve; so that the tenth lies parallel to the seventh. 

 Their inner surfaces are furnished with numerous rows of very flat spiaes. In the oldest 

 specimen there are about twelve rows, making the total number of spines for every joint 

 several hundreds. None of these spines, however, show the original shape ; they are all of 

 them broken by use or by age, and those placed towards one side especially are very short 

 and rudimentary. On the other side they grow longer (PI. X. fig. 2), and, covered 

 by this outermost row of longest spines, some short thimble-shaped knobs (fig. 5) are to 

 be observed. Such is at least the condition of the flattened spines on the last four joints of 

 the ovigerous legs of the gigantic male dredged at Station 146. The specimen second 

 in size is a great deal smaller and in all probability is not quite adult. Here the 

 spines, placed in about eight rows, show a much more regular shape (fig. 3) ; their 

 margins are furnished anteriorly with very small hairs. These hairs are rather 

 firm, are not at all injured by the action of alcohol, and must not, I believe, be con- 

 sidered as cilia. The spines are in the middle a great deal narrower, and broader again 

 at the extremity, the broader part has the shape of a rhomb. In the earliest stage the 

 spines are much smaller and beautifully spatulate. The small hairs extend here to beyond 

 the middle (PL X. fig. 4). 



This species has exceedingly long legs. The first three joints are very small, the 

 three following very long ; the fourth is the longest, the fifth a little shorter, the sixth 

 again a little shorter ; the two last joints are small again ; the second tarsal is only half 

 as long as the first. The claw measures about one-third the length of the second tarsal 

 joint ; there are no auxiliary claws. The joints of the leg, from the fourth to the 

 eighth, gradually decrease in tliickness. The hairs, which on the legs of the large adult 

 specimen are extremely smaU and sparse, are stronger and more numerous on -the legs of 

 the younger specimens. 



In regard to the sexes of the specimens of this species dredged during the voyage of 

 the Challenger, I am sure only of the gigantic specimen. This is a male ; it shows genital 

 openings on the ventral surface not very close to the distal margin of the second joint of 

 the two posterior pairs of legs. About the other specimens, whose genital openings I fliiled 

 to observe, I am in doubt whether they are young males or females. The colour of the 

 specimens is light yellow, nearly the same as that of all other Pycnogonids preserved in 

 spirits. The large full-grown male, however, is of a much darker orange-red colour, with 

 beautiful red bands over the proboscis, at the extremity of the joints of the legs, &c. 



Habitat. — Colossendeis gigas, seems to occur in difi"erent parts of the southern 

 ocean ; it was dredged at 



Station 146. December 29, 1873. Lat. 46° 46' S., long. 45° 31' E. Depth of the 

 sea, 1375 fathoms. Temperature of the bottom, 1'5° C. Sea bottom, globigerina 

 ooze. 



Station 147. December 30, 1873. Lat. 46° 16' S., long. 48° 27' E. Depth of the 



