30 THE APODOUS HOLOTHURIANS 



The calcareous ring is very narrow, much as Dendy ( '97) figures it for dune- 

 dinensis. The wheel-papillae are conspicuous in the three dorsal interradii, 

 especially anteriorly. The sigmoid bodies are also collected, on the dorsal 

 side, into little groups which appear to the naked eye as numerous small 

 whitish papillae. 



T^NIOGYBUS CONTORTUS (Ludwig). 



There are 3 specimens of this species from the Strait of Magellan, 

 "Albatross" Station 2771, lat. 51 34' S., long. 68 W. They were dredged in 

 91 m., and measure 40-45 mm. long. 



SCOLIODOTA JAPONICA (v. Marenzeller). 



There is a single specimen in the collection, one of those taken by the "Chal- 

 lenger" at Port Jackson, New South Wales, and already described by Theel. 

 There can be no doubt that wheels are entirely wanting. 



MYBIOTROCHUS BINKII Steenstrup. 



There are rather more than 600 specimens of this little holothurian in the 

 collection, from 10 widely separated points : Point Belcher, Arctic Ocean, 

 16 m., sand; off the banks of Newfoundland, lat. 45 35' N., long. 55 01' W., 

 121 m. ; Barden Bay, Inglefield Gulf, 18-72 m. ; Norway ; Cape Smyth, Alaska ; 

 Aberdore Channel, east of Alger Island; Point Barrow, Alaska; Greenland; 

 Kara Sea; and "Albatross" Station 3440, Bering Sea, lat. 57 05' N., long. 

 170 41' W., 86 m. The abundance of material from Bering Sea and the banks 

 of Newfoundland led me to make a comparison of the calcareous wheels of 

 the specimens from those points. These measure 164 to 328 n in diameter, 

 but average about 245 /*, and the very great majority are near that figure. 

 The wheels of specimens from the banks average 16.5 spokes and 26.5 teeth on 

 the rim; the number of spokes, therefore, is about 0.62 that of the teeth. In 

 specimens from Bering Sea the average was 17 spokes and only 23.7 teeth, or 

 about 0.71. This difference was found in counting 10 wheels chosen at ran- 

 dom in each of 10 specimens from each locality. It is not probable, however, 

 that it really has any significance, as the number of spokes and teeth shows 

 such great diversity, and there is apparently no correlation between the two ; 

 for although the wheel with the smallest number of spokes (12) had the small- 

 est number of teeth (16) and the wheel with the largest number of spokes (22) 

 had the largest number of teeth (30), wheels with only 15 spokes had as 

 many as 29 teeth that is, a ratio of only 0.51 while others with 17 spokes 

 had only 18 teeth, or a ration of 0.94. In every case, however, there were more 

 teeth than spokes. It is interesting to compare these figures with those given 

 by Ostergen ( :03). He says the wheels of specimens from eastern Siberia aver- 

 age from 240 to 260 M, while those of Norwegian specimens averaged 208- 



