BRACHIOPODA. 
183 
SUPPLEMENTARY NOTE ON THE GENUS KUTORGINA. 
Some interesting observations which bear upon the phylogenetic relations of 
this obscure genus, have recently been made by Mr. G. F. Matthew, in a paper 
entitled “ Canadian Organisms in Acadia,” published in the Transactions of the 
Royal Society of Canada, article xii, jd. 135. 1890. The author has described 
and illustrated the development of his species, Obolus pulcher (see Plate IY k, 
fig. 22), and though it may not be proven that this form can be safely included 
within the genus Obolus, it is distinctly oboloid. These observations are based 
upon adult shells which retain evidence of differential stages of shell-growth 
with sufficient distinctness to allow of the following subdivision: 
“ (1) Embryonic. Formation of the embryonic shell. 
“ (2) Larval. Lengthening of the hinge-line and acquisition of mantle 
margins. 
“ (3) Adolescent. Fixation of the hinge-line, otherwise as the last, except 
the radular ornament becomes irregular. 
“ (4) Adult. Absence of radular ornamentation on the valve and great 
expanse of the mantle margin.” 
In the earliest stages represented (plate viii, figs. 1 a-e, brachial valve, figs. 2 
a-d, pedicle-valve), the hinge is straight and long, making the greatest diameter 
of the shell, the umbo of the pedicle-valve is elevated and the cardinal area 
erect and with a triangular pedicle-aperture. The resemblance to Kutorgina 
in the growth-stage is at once striking, and it may serve to indicate the sub¬ 
ordinate value of this genus in its relation to the oboloid stock. 
