THE BRACHIOPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 385 
rubicunda* is possibly its nearest ally, but, owing to the strongly developed septum, 
its place in the genus Terebratella is precluded, and therefore it might possibly be 
described as the magaselliform ancestor of 7. rubscunda. 
In my opinion, judging from Buckman’s figure, the original of which would appear 
to be partly a cast, this form is more closely allied to one or other of the numerous 
variations of the polymorphic 7. dorsatu. 
If comparisons be made with TJ. dorsata, var. submutica, F. and O. (op. cit., 
p- 279, pl. xi. figs. 1-6), a very striking resemblance is noticeable. In this variety 
the radiating sculpture is almost absent, and the appearance of the shell is less 
transverse than in the typical form. 
It might be argued, however, that the deltidial plates in these specimens are fully 
developed, thus denoting an adult condition, but in examples of this form from 
Burdwood Bank there are specimens which show the deltidial plates only partially 
developed, and, as is usual in 7. dorsata, the radiating ribs of the exterior are visible 
also on the interior of the valves and would thus be impressed upon a fossil cast of 
this species. 
To my mind it would be much more reasonable to refer the Cockburn Island fossil 
to a magaselliform stage of Terebratella dorsata, and more especially to the var. 
submutica, F. and O., than to go so far away as New Zealand for a comparison. 
According to Fischer and OErHuertT (1892), 7. dorsata is not cited among the 
fossils of Patagonia by d’Orsiany, Darwin, and Sowersy, but on the contrary is given 
by Hurron (1873) and Hector (1886) for the New Zealand Tertiaries (Lower Miocene- 
Ahuriri formation) from Cape Rodney, Auckland, N. Island, associated with the 
recent Rhynchonella ngricans, Sow. 
This reference, if authentic, is of considerable importance as indicating significant 
climatic changes during the deposition of these beds. 
One feels disposed, however, in the light of present knowledge, to question the 
correct identification of the New Zealand species, and to consider the possibilities of 
the form in question being referable to the well-known and variable 7. cruenta or a 
probable ancestor of that species. 
Terebratella sp. (P\..II. fig. 10.) 
Hab.—Station 346; lat. 54° 25’ §., long. 57° 32’ W. (Burdwood Bank), 56 
fathoms. December 1, 1903. Sea bottom, Bryozoa. Temperature 41°°8 F. 
Obs.—Amongst the smaller specimens of Brachiopoda from this station are one or 
two examples whose generic and specific positions are somewhat doubtful. 
The two largest and most perfect of these questionable forms measure :— 
Length. Breadth. Thickness. 
Nicol : . 13°25 10°5 6°75 mm. 
istic ; 6 14 8°5 
9 
* A New Zealand recent species. 
