i8 
S. s. BUCKMAN, 
(Schwed. Südpolar-Exp. 
Genus Magasella, Dall. 
Two species may be placed in this genus, one M. antarctica, nov., with some 
uncertainty, and the other with certainty because it shows the characteristic loop and 
moreover is a form parallel with a Recent Boreal species. 
According to Davidson (Challenger Brach. i8) recent species of the genus Magasella 
are almost if not quite confined to the temperate zones: they are found, for instance, 
off the Aleutian Islands and Japan in the North Pacific, off S. Australia, and New Zealand, 
in Moreton Bay and Straits of Magellan, etc. in South Pacific; off the Canaries of the 
North Atlantic, and off the Falkland Isles of the South. Their range in depth is from low 
water to 6o fathoms; but they are more usually found living in about 5 to 15 fathoms. 
Magasella antarctica, sp. n. 
Plate I, fig. 17. 
Description: Subcircular, lenticular; dorsal valve gibbous, most so near the 
umbo, sloping thence to the anterior margin, and having a very slight median de- 
pression; ventral valve gibbous, most so about the middle, showing for its whole 
length a slight median carina; both valves crenulate towards the anterior margin and 
the whole test beautifully punctate. Beak short, foramen large, incomplete; delti- 
dial plates very small. Internal arrangements unknown, but a stout septum reaches 
nearly to the anterior border. 
Remarks: This species is much like the figure and description of Terebratella 
Tepperi^ Tate (Aust. Tert. Pal. pi. IX, figs 8 a— 8 c, p. 31), but that is said to have 
a plain front margin, and a remarkably short medial septum. In the Antarctic form 
the front margin is incipiently multiplicate, while the septum reaches quite 3 /^ths 
towards the margin. It has some resemblance to Magasella patagonica and M. 
supfusa figured by Davidson (Recent, XVII, 12 — 15); but they are both somewhat 
different in shape, and more crenulated. 
It is a little like Terebratida foncki^ Phillipi, (PI. XLIX, f. i, p. 218); but the 
crenulations, the less carinate ventral, and more gibbous dorsal valve distinguish it. 
To Terebratella rubicuncia it is possibly most nearly allied; but the dorsal 
sinuation and the ventral plication are not so strongly developed, while the long 
septum forbids placing it in the genus Terebratella; but possibly it might be de- 
scribed as the magaselliform ancestor of T. rubicimda. 
Terebratella ncozelandica^ Jhering, 328 = T. dorsata; SuESS, XIV, 6, is too pli- 
cate, and has the fold and sinus too much developed. 
Locality: Cockburn Island (13), off Graham Land, Antarctica. 
Formation: Glauconitic Bank. 
Material: Two specimens, one a good deal broken. The larger of the two 
examples is figured. 
