104 Canadian Record of Science. 
It is eminently characteristic of the Utica wherever that 
formation has been traced in its natural position over- 
lying the Trenton formation in Canada and the United 
States ; so that its presence at Murray Bay affords good 
evidence upon which to determine the geological hori- 
zon. The specimens from Murray Bay exhibit the 
radiating lines very well, showing no appreciable varia- 
tion compared with Ottawa or Collingwood specimens. 
4, SIPHONOTRETA sp.—This is undoubtedly the most interest- 
ing and rarest form in the collection. A cursory ex- 
amination of this form and the associated specimens 
was made some three years ago, but at that time it was 
considered and grouped along with the specimens of 
Leptobolus insignis; but a closer examination having 
been made last spring, it was found that the surface of 
the shell and other parts presented all the essential 
characters of a true Siphonotreta (de Verneuil). The 
specimen is preserved as a mould or cast of the shell, 
exhibiting the spines all around the outer margin and 
sides, and may possibly be a young individual of, or close- 
ly related to, Siphonotreta Scotica Davidson, a species re- 
corded by Mr. J. F. Whiteaves in 1883 from the Utica 
formation in a paper read by him at the Montreal meet- 
ing ofthe A. A. A.S. Additional notes on that species 
were made by the writer in the “Ottawa Naturalist” 
for December, 1887, and in Vol. II. No. 3 of the Ottawa 
Field Naturalists’ Club Transactions, No. 7, p. 347. 
The following notes are taken from the Murray Bay 
specimen, which is probably the larger value: Dimen- 
sions as follows :—Length of the shell, 1:75 millimetres ; 
breadth, 1°8 millimetres ; length of the setaceous spines 
in front, °5 millimetre. 
This minute form agrees very well with the characters 
such as a young form of Siphonotreta Scotica, Davidson, 
and its Canadian variety might assume or be expected to 
have from an examination made of many adult individuals 
collected in the Utica of Gloucester, near Ottawa, but there 
is also a very close resemblance between the Murray Bay 
