16 
THE VOYAGE OF H.M.S. CHALLENGER. 
Studer’s Sigmodota purpurea, which is found living in the Strait of Magellan and at 
Kerguelen Island. 
Chirodota contorta, Ludwig, 1875 (PI. II. fig. 2). 
Habitat. — Marion Island, 50 to 75 fathoms; several individuals. Off Christmas 
Harbour, 120 fathoms; one individual. Balfour Bay. 20 to 60 fathoms; several 
specimens. Betsy Cove, 25 fathoms; one individual. Station. 313, January 20, 1876 ; 
lat. 52° 20' S., long. 67° 39' W.; depth, 55 fathoms ; bottom temperature, 47'8 ; sand ; 
a few individuals. Station 314, January 21, 1876; lat. 51° 35' S., long. 65° 39' W.; 
depth, 70 fathoms; bottom temperature, 46 '0 ; sand; numerous individuals. 
The tentacles with ten to twelve digitations, the terminal of which are largest. The 
sigmoid deposits (PI. II. fig. 2, h) exactly resemble those described by Studer in 
Sigmodota purpurea. They reach a length of about 0’28 mm., while the diameter of the 
wheels is only 0T2 mm. The specimens brought home from Station 314 differ from 
the others in having the aggregations of wheels much more crowded, whde the aggrega- 
tions of wheels (PI. II. fig. 2, a), especially in the individuals obtained at Marion Island, 
are very scattered, so that they almost appear at first sight to be devoid of them. The 
specimens examined by me differ from Ludwig’s type in their violet colour. It seems 
very peculiar that all the individuals dredged by the Challenger Expedition in several 
localities at the Kerguelen Islands, as well as in or in the neighbourhood of the Strait of 
Magellan, belong to Ludwig’s Chirodota contorta. Not a single specimen of Studer’s 
Sigmodota purpurea was obtained, therefore I cannot help thinking that the very 
scattered aggregations of wheels have escaped the attention of Studer, because of the 
sigmoid bodies being so conspicuous by their number as well as by their size. 
Chirodota australiana, Stimpson, 1856. 
Habitat. — Port William (New Zealand, Falkland Islands ?) ; depth, 5 to 10 fathoms ; 
two specimens. 
The species is nearly related to Chirodota contorta, and differs from it mainly in 
possessing but ten tentacles, each with about eight digitations, and in having a single 
Polian vesicle. Length of the specimens, 35 mm. Colour in alcohol, light dirty brown. 
The wheels and sigmoid bodies seem to be present all over the body. Diameter of the 
wheels, 0T4 mm. Length of the sigmoid deposits about 014 mm. From the macerated 
state of the animals, the arrangement of the aggregations of wheels is not distinct. A 
single madreporic canal is present. The reproductive organs consist of two very long, 
slender, simple genital tubes. The Challenger specimens seem to agree in all respects 
with the species of Stimpson. 
