BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



5mm 



FIGURE 1. Centrodorsals of: a, Notocrinus virilis Mortensen from 

 Terra Nova station 341, B.M., 1914.8.12.392; 4, N. mortenseni John 

 from B.A.N.Z.A.R.E. station 40, B.M., 1948.1.7.167. 



segments which terminally are scarcely twice as long as broad. The terminal segments 

 are coarsely spinous on the dorsal side. 



The testes of the males are very large, forming two alternating rows of conspicuous 

 white bodies along the dorsal sides of the arms between about pinnules 3 to 14, each 

 corresponding to a pinnule. They are about 4 mm. long. The ovaries of the females 

 are smaller, only about 2 mm. long, similarly placed at the bases of the pinnules. (See 

 part 2 of this work, plate 55.) 



The sacculi are few and very inconspicuous, irregularly arranged. 



The mouth is central. The anal tube is very conspicuous, situated near the oral 

 angle of the posterior interradius. The disk bears numerous thick plates which form 

 a close pavement between the arm bases, becoming more scattered toward the ventral 

 surface. Ventrally they are especially prominent in the anal iiiterradius and on the 

 basal portion of the anal cone. Among these last there is usually one very conspicuous 

 plate about twice the size of the other plates, or even larger. Mortensen says that 

 there can be no doubt that this is the radianal ("anal") which accordingly persists 

 throughout life in this species. In the oral angle of each interradius there is a fairly 

 conspicuous plate which Mortensen says evidently represents the oral. It is, however, 

 not wholly constant in its appearance. 



Color. Most of the specimens are, in alcohol, reddish at the base of the centro- 

 dorsal; the arms are straw colored and the cirri white. 



Notes. The somewhat damaged specimen collected by the whaler Bransjield at 

 the South Shetlands according to Grieg has the largest cirri 40 mm. long with 55 seg- 

 ments. The distance between the radial and the first syzygy is 3 mm. 



The specimen from Terra Nova station 341 has the arms about 160 mm. long. 



The Discovery Investigations specimens range from 28 to 130 mm. in arm length. 

 Their cirri showed a wider range of variation than did those of Mortensen, being 

 XXI-XLII, with 36-76 segments. 



The specimen from Discovery Investigations station 1658, in the Ross Sea and two 

 Terra Nova specimens from station 295 in the same area differ from typical specimens 



