430 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Septa, 24 in three cycles, the third rudimentary. There is a tend- 
ency for the first two cycles to be irregularly developed so that the 
symmetry is apparently quadrameral. Columella rudimentary. 
Named from Cowichan Lake, upon the southern shore of which 
the fossil was found. 
Comparisons. — This species agrees \er\' closely with /. parva 
Gregory of the Upper Putchum Beds (upper Middle Jurassic) of 
India ^ in forming encrusting sheets of polygonal, rather deep and 
Small corallites. The number of septa is similar but in our species 
they are more rudimentary in having the third cycle very poorly 
developed and with no indications of a fourth cycle. The walls of 
our species are also thicker. 
It also agrees very closely with /. richardsoni Edwards and Haime 
of the Inferior Oolite (lower Middle Jura) of England - differing 
principally in its more rudimentary third cycle of septa, and its 
thicker walls. 
Isastrea vancouverensis n. sp. 
PL 40, fig. S; PI. 42, fig. 17. 
Corallum massive; closely crowded corallites irregularly hexagonal 
or rounded, united directly by their relatively thin walls. Calices 
exceedingly deep, with average diameter of about 2 mm. In the best 
preserved corallites the septa reach almost to the center. The septa 
are very poorly preserved, seldom appearing except as vertical ridges 
on the inner walls. They are apparently from 20 to 30 in number 
and there are indications of two cycles. There is a suggestion of the 
presence of a spongy columella and of tabulae. 
Named from the group in which the Sutton formation occurs. 
Comparison. — In its tall corallites and deep calices it resembles 
/. oblonga (Fleming) from the Portland series (Upper Jura) of Eng- 
land.^ It differs mainly in its much smaller size (diameter of calyx, 
2 as against 4 to 5 mm.) and is less regularly hexagonal or pentagonal, 
many being semicircidar in cross-section, thus indicating a more 
primitive species. 
1 J. W. Gregory. The Jurassic Fauna of Cutch. The Corals. Mem. Geol. Surv. 
India, Pateontol. Tndica, ser. 9, 1900, vol. 2, pt. 2, p. 129. 
= Edwards and Haime. A Monograph on British Fossil Corals. PaliBontogr. Soc 
London, 18.50, vol. 1, p. 13cS, pi. 29. figs. 1, la. 
3 J. Fleming. British Fo.ssil Corals, 1850, pt. 1, p. 73, pi. 12. 
