440 PEECr SLADEN TEUST EXPEDITIOJs\ 



characteristic. In the present species they resemble those of Liothyrina vUrea as 

 fio"ured by Blochmann *, but are somewhat more densely branched (fig. 2) ; their main 

 characteristic is the rounded excavation of the space at the junction of the minor 

 ■with the major branches ; the convexity of this arcuation being always proximal or 

 toward the main focus or centre of the spicule. The specimen figured was taken from 

 the posterior part of the mantle of the dorsal valve. 



2. Kranssina gardinerl, sp. n. (Plate 26. figs. 3-6.) 



Shell rude and solid, greyish white, much the same shape as Muhlfeldtia triincata 

 when young, while the shell has a width of 13 and a height of 12 mm. As it grows, 

 however, the outline elongates proportionally more than it Avidens, and an adult measures 

 24*5 mm. from beak to anterior margin and 23 mm. at right angles to this line at the 

 broadest part of the shell. The outline is then roughly rhombic. The hsemal valve is 

 slightly excavated mesially by a shallow depression, the pedicel valve having a corre- 

 sponding convexity, but the flexuosity is hardly noticeable. The pedicel valve is very 

 slightly more convex than the other, the total diameter of the adult being about half 

 its length ; in the young the haemal valve is proportionately flatter. 



As in most species of the genus, the beak is short and wide, the pedicel short, the 

 foramen wide and anteriorly incomplete, the margins usually more or less eroded or 

 defective ; on each side of the foramen is a wide flattened area of somewhat irregular 

 shape, but always wider than long. 



The sculpture of the valves is formed by coarse, rounded, radial ridges, strongest 

 mesially, with subequal roundly excavated interspaces ; these ridges are mostly con- 

 tinuous from the beaks, and when they increase, toward the anterior part of the valve, 

 it is more commonly by bifurcation than by intercalation. Of these ridges there are 

 about forty in the adult, the most lateral being finer and closer-set than the others. 



The internal sculpture of the valves, which is peculiar and rather characteristic in this 

 genus, and the depressed muscular scars, are shown by the figures better than could be 

 done by a verbal description. 



From Kraussina rubra and oapensis this species difi'ers in wanting the characteristic 

 red colour, in having a difi'erent sculpture from the former, and difierent apophyses from 

 the latter. It is not necessary to compare this species with K. pisum and the other 

 small species. The sculpture of the interior of the valves, as illustrated by the figures, 

 is quite different from that of any of the other species. 



The species is named in honour of the leader of the expedition, Mr. J. Stanley 

 Gardiner. 



3. Hemithyris sladeni, sp. n. (Plate 26. figs. 7-12.) 



Shell small, inflated, mesially flexuous, of a translucent waxen white, more or less 

 suffused in some specimens with very pale brown ; general form rounded-triangular, the 

 excavated flexure being in the pedicel valve, but the haemal valve is so inflated that the 



» Zeitschr. fiir wlss. Zool. sc. (190S) Taf. 37. %. 10. 



