232 THE OTTAWA NATURALIST. | March 
BOREMYS, A NEW CHELONIAN GENUS FROM THE 
CRETACEOUS OF ALBERTA.* 
By LAWRENcE M. Lampe, F.G.S,, F.R.S.C., Vertebrate Palzontologist to 
the Geological Survey of Canada. 
The writer described in the January number of this journal a 
new species of Pleurosternid turtle from the Cretaceous rocks 
(Belly River or Judith River formation) of Red Deer river, Alberta. 
The material on which the species was based, was obtained by 
the writer on Red Deer river in 1898 and 1901, and consists of 
the entire plastron with the anterior half of the carapace of one 
individual (type), a second carapace, and parts of other plastra, 
all of the specimens being from the same locality and horizon 
near the mouth of Berry creek, a tributary of Red Deer river. 
The species in question was named pulchra and was referred to 
Leidy’s genus Baéna. It is now considered that this species be- 
longs to a new genus, distinct from Baéna, for which the name 
Boremys, indicative of a northerly habitat, is proposed. 
The carapace of Boremys pulchra is remarkable in having a 
row of three large supramarginal shields on each side, in line with 
the 2nd, 3rd and 4th vertebral shields, between the costals and 
the marginals. The total number of costal shields is twelve, there 
being the normal number, eight, with one on each side of the 1st 
vertebral and one on each side of the 5th vertebral. 
The presence of supramarginals is regarded as a generic 
character of some importance which, taken in conjunction with the 
structure of the plastron, indicates a hitherto undescribed type of 
Pleurosternid quite distinct from Baéna, its probable nearest ally. 
As regards the anterior and posterior costal shields of 
Boremys pulchra, the anterior ones at least occur in Baéna 
arenosa, B. undata and B. hebraica, as described and figured by 
Cope in his ‘‘ Tertiary Vertebrata,” vol. ili, 1884. 
The genus Boremys may be characterized as follows :— 
Supramarginal sbields present in the carapace ; mesoplastra 
well developed, in contact in the median line for some distance ; 
* Communicated by permission of the Acting Director of the Geological 
Survey of Canada. 
wi 
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