370 DISCOVERY REPORTS 



St. 391. 18.iv.30. 55° 481' S, 52°35'W south of Falkland Islands. 4 m. tow-net, 1200- 

 1300 (-0) m. 



Three specimens: one tvyvillei, 96 mm. diam., central disc 56 mm., no furrows on pedalia, 

 annular zone very small, slightly notched on margin of central disc, no gonads, Broch's group IV, 

 very dark, but somewhat faded, transitional stage to verrilli; one verrilh, 18 mm. d.am., Broch's 

 group III ; one bairdi, 12 mm. diam., Broch's group III. 

 St. 592. 15.1.31. 64° 17' 8,75° 31' W, south of South Shetlands. i m. tow-net, 350-124 m. 



One specimen oUvyviUei, in fair condition, 62 mm. diam., central disc 38 mm., furrows on central 

 disc and pedalia, coronal furrow deeply pigmented, Broch's group IV, gonads well developed but 

 hardly visible from outside, flat, central lens overhanging, no annular zone visible. 

 St. 595. 16.1.31. 65° 13I' S, 70° 26i' W, south of South Shetlands. i m. tow-net, 380-133 m. 



One specimen oiwyvillei, in fair condition, 82 mm. diam., central disc 51 mm., annular zone very 

 narrow, furrows on central disc 4 mm. broad, 8 mm. long, ring muscle with traces of reddish brown 

 pigment, greenish yellow, furrows on pedalia, coronal furrow and subumbrella with dark purple 

 pigment, Broch's stage IV, gonads whitish, well developed. 

 St. 563. i.i.31. 66° 58^' S, 79° 32I' W, Bellingshausen Sea. i m. tow-net, 450-180 m. 



One specimen of wyvillei, very beautiful, 78 mm. diam., central disc 51 mm., height 25 mm., 

 Broch's stage IV, traces of pigment on the greenish circular muscle, notches on central disc very 

 broad (4! mm.), 6 mm. long, deeply pigmented. 



St. WS552F. 3.xi. 31. 68° 53' to 68°5o'S, 13° 03' to 13° 03' W, north-west of Coats Land. 

 I m. tow-net, 460-360 m. 



One specimen of wyvillei, 72 mm. diam., central disc 42 mm., in fair condition, Broch's pigment 

 group IV, furrows on central disc very conspicuous, 4 mm. broad, 5 mm. long, the whole subumbrella 

 covered with a layer of reddish brown pigment, coronal furrow, ring muscle, all furrows on pedalia 

 and between them and on the lappets pigmented, no annular zone, gonads well developed, 

 whitish. 



The three diflFerent types of this species have been treated so often in the literature 

 that I can restrict myself here to a few observations. 



Furrows. Plate XV, fig. 4, shows distinctly that if twenty-four pedalia are present 

 there are as a rule twenty-three furrows on the central disc. There is no furrow on the 

 latter in the radius of the septal notch above a very broad pedalion which has no furrow 

 either. This is a trace of bilateral symmetry. As will be seen from the list above I 

 recognize ninety-one specimens as wyvillei (typica), seventy-two as the boirdi form 

 and twenty-one as the verrilli form — on the basis of the furrows on the central disc. 

 The discrimination of these three types is not difficult with the Qxtremt?,—wymllei on 

 one side, bairdi on the other — but in many cases it was not at all easy to say whether a 

 given specimen belongs to the verrilli or tvyvillei type. In those cases judgment is often 

 very arbitrary. Deep broad radial furrows are only to be seen on large specimens. On 

 small specimens it is almost impossible to say, with any certainty, whether they belong 

 to one or other form, because there is considerable variation in the breadth of the 

 furrows, not only in different specimens of the same form, but also in a single specimen. 

 According to Broch (191 3), who recognizes the species wyvillei next to bairdi as a good 

 species, there is a great resemblance between bairdi and verrilli. I found more transi- 



