i02 DISCOVERY REPORTS 



Dentition. Fig. G, 6, p. 189. 00+4+1+4 + 00. Very similar to that of ' Margarita striata' = Pupillaria 

 cinerea Couth (Thiele, 1891, pi. 25, fig. 9) from Gulf of St Lawrence. Both have the central tooth 

 with a circular base and laterals of the same form except that each is cut away on its inner side. 



Thiele's drawing of the radula of 'striata' shows a vestigial fifth lateral and a very weak innermost 

 marginal. In biangulata there is no trace of a fifth lateral, and the innermost marginal is the largest of 

 that series, but it is not disproportionately large as in the Calliostomids. 



Animal. There are six pairs of epipodial tentacles — the sixth from the front long and slender, almost 

 twice the length of the other five, which are of approximately equal size. Cephalic tentacles moderately 

 long, blunt and flattened. Eye at the end of a short stalk, lying at the outer side of the base of each 

 tentacle. The stalk is confluent with a short veil which crosses the base of a tentacle but does not join 

 up with its opposite member across the head. Head narrow in front and produced into a wrinkled 

 proboscis, with a frilled edge. Epipodial fringe continued to the area in front of the head in an elaborate 

 series of folds. 



Subfamily Solariellinae n.subfam. 



This new subfamily is provided for the group of genera Solariella, Machaeroplax and Cidarina. The 

 shells are conical, openly umbilicated, with a more or less circular simple aperture, and sculpture of 

 spiral keels or ribs, usually crenulated or granulated below the suture and bordering the umbilicus. 



The radula has an approximate formula of 10 + 5 + 1 + 5 + 10, the most distinctive feature being the 

 small number of marginals. In all other Trochoid groups the marginals are so numerous and crowded 

 that it is impossible to determine their exact number. Other distinctive radular features are the very 

 pronounced dip to the centre of each row and the elongate shape of the two outer laterals which 

 resemble the enlarged functional inner marginals of the Calliostomids. 



Genus Solariella Searles Wood, 1842 

 Type (monotypy): Solariella maculata S. Wood 



The genotype is from the English Pliocene and is a heavily carinated shell with prominent beading 

 or crenulations both at the suture and on a ridge bounding the wide funnel-shaped umbilicus. 



There is a group of subantarctic species, Trochus {Margarita) brychius Watson, from 900 miles 

 south-east of Kerguelen Island in 900 fathoms, T. (Margarita) charopus Watson from off Kerguelen 

 Island in 105 fathoms, var. caeruleus Watson from off Heard Island in 175 fathoms and the new species 

 kempi described below. These have the general features of Solariella, but lack the sutural and umbilical 

 crenulations. 



The radula of kempi n.sp., however, is essentially similar to that of varicosa Mighels & Adams from 

 Newfoundland to Nova Zembla as figured by Pilsbry (1889, pi. 50, fig. 17) and biradiatula Martens 

 from Dar-es-Salam in 400 m. as figured by Martens & Thiele (1903, pi. 8, fig. 37; see Text-fig. G, 12). 

 Both these species have crenulations, but the other shell characters are not very similar, neither are 

 they to the Pliocene genotype nor to the subantarctic group mentioned above. This subantarctic group 

 is for the present retained in Solariella pending a revision of the members of the subfamily. 



Solariella kempi n.sp., PI. I, fig. 6 



Shell globosely conoidal, thin, sculptured with closely spaced, sharply raised, narrow, spiral cords 

 and dense axial interstitial threads; widely umbilicate. Whorls 5f, regularly increasing and including 

 a minute apparently smooth helicoid protoconch of one whorl. First post-nuclear whorl with three 

 wide-spaced, narrow, sharply raised, spiral cords, second with four, increasing to fifteen on the penulti- 

 mate, by the addition of intermediate cords, and about sixty on the body whorl from the suture to the 

 edge of the umbilical cavity ; about thirty within the umbilicus. The whole surface is crowded with 



