10 
VICTORIA MEMORIAL MUSEUM. BULLETIN NO. I 
brachials immediately succeeding an axiliare (Plate I, fig. 4) 
lends some colour to this suggestion. On the other hand such 
arm-structure is quite common among Dicyclica Inadunata, The 
sutures between the brachials of Ottawacrinus are not curved as 
they so generally are in the Flexibilia. Further, its anal tube is 
far more reminiscent of the Inadunata, especially of the so-called 
Fistulata, than of any member of the Flexibilia. The stem is 
like that of many other Inadunata, and has no persistent proxi- 
male. On this last feature, however, no stress should be laid, 
for a proximale is, I understand, no longer regarded as diagnostic 
of Flexibilia by the survivor of the two authorities who had pre- 
viously maintained it. It is a matter on which I was always 
sceptical (see Geol. Mag., July, 1898, p. 324). There is in Ottawa- 
crinus a slight widening of the stem towards the cup, but, since 
this amounts to no more than 0 • 7 mm. in a diameter of 3 • 2 mm. 
and in a length of 5 * 4 mm., it is scarcely enough to constitute a 
proximal cone such as is so common in Flexibilia. Turning to 
the cup we observe no structures that may not be as readily 
paralleled in Dicyclica Inadunata as in Flexibilia; indeed, more 
so, for the presence of five distinct infrabasals is quite foreign to 
the Flexibilia. 
On the whole, then, there appear no good grounds for associa- 
ting Ottawacrinus with the Flexibilia, although it would be diffi- 
cult to deny that the early Flexibilia may possibly have originated 
from Ottawacrinus and allied genera. It is not easy to draw a 
line between the Flexibilia Impinnata and the Dicyclica Inadun- 
ata. But apart from that speculation, neither the new interpre- 
tation suggested in the present paper nor the additional facts 
brought to light involve any change in the systematic position of 
Ottawacrinus . Indeed, the view taken in the “Treatise on 
Zoology’' (p. 178) is confirmed by the discovery of the arm- 
dichotomy and the structure of the anal tube. Retaining the 
Order Dicyclica Inadunata, Sub-Order Dendrocrinoidea, and 
Family Dendrocrinidae, as defined in that book, we may give 
the following: — 
Diagnosis of Ottawacrinus. — A Dendrocrinid with 5 IBB; with 
all RR transversely bisected, with r. post, and r. ant. Ri resting 
directly on the corresponding BB; with anal x resting directly 
on post. B, and supporting two tube-plates. 
