lO 
s. s. BUCKMAN, 
(Schwed. Südpolar-Exp. 
Family Rhynchonellidae, Gray. 
Genus Hemithyris, d’Orbigny. 
Hemithyris squamosa, HuTTON sp. 
Plate I, fig. 13. 
1873. Rhynchonclla squamosa, HUTTON, Cat. Marine Moll., p. 37. 
1877. Rhynchonclla cœlata, M‘COY M.S., WOODS, Tert. Dep. Austr. 77. 
1880. Rhvnchonella nigricans, var. pyxidata; Davidson (pars), Challenger, Brach. 
59; and 1887, Recent Brach. 171, quoting WOODS above as synonym. 
1880. Rhynchonella squamosa; Tate, Austr. tert. Palliobr., PI. XI, figs 9 a (9 b?). 
Description. — ‘i?. squamosa, sp. n. — Shell irregular, more or less orbicular; 
valves inequal, the ventral flatter, and with a deep groove; dorsal valve very con- 
vex; both with fine radiating scaly striæ. Length 0,7, breadth 0,75, height 0,5. 
Localities. — Broken River (M). Easily distinguished from R. nigricans by its more 
numerous striae.’ 
The above is Hutton’S original description and remarks; he gave no figure. 
The following describes the Antarctic fossil: Wider than long; valves somewhat 
irregular and uneven in mode of growth, covered with many distinct radiating striae; 
slight mesial fold; short, distinct sinus in ventral valve. 
Remarks. — The specimen agrees very well with TaTE’s PI. XI fig. 9 a, but 
not so satisfactorily with 9 b. 
Davidson’s Rhynchonella nigricans var. pyxidata (Chalk Brach. IV, 14; Re- 
cent Brach. XXIV, 20) is not so transverse, is longer, stouter, with more gibbons 
valves, less distinct sinus, and coarser ornamentation. 
Locality. — Cockburn Island (13), off Graham Land, Antarctica. 
Formation. — Glauconitic Bank. 
Material. — One example, incomplete; being incomplete dorsal valve with an- 
terior part of ventral valve attached showing sinus. 
Distribution of species and allies. — R. squamosa is found in the Tertiaries in 
Australasia — in Tasmania as R. ccclata', R. nigricans and R. pyxidata are recent 
species still living off the coast of New Zealand and the Kerguelen Isles. 
