20S CONTRIBUTIONS TO CANADIAN PAL.EONTOLOGT. 



hydeo:medus.e. 



Hydroida. 



AcTiNOSTROMA Whiteavesii, Nifbolsoii. 



Aclinoslroma Whiharesii, Nicholson. 1S91. Ann. and IMii;.;. Nat. Hist., vol. VII, 

 Sixth Ser., p. 320, pi. ix, figs- 3 and 4, also woodcut, fig. 2, in test. 



Peace Eiver, near the mouth of Little Red Eivev, Professor ^facoun, 

 lst5 : two specimens. 



ECHINODEEMATA. 



Crinoidea. 



Arachnocrinus Canadensis. (N". Sp.) 

 Plate 2S, tigs. 2 and 2a. 



Calyx (or dorsal cup) very small, hemispherical and about one fourth 

 broader than high. Underbasals small, apparentlj" rhomboidal, but 

 pai'tly covered by the column : basals rather large, four pentagonal and 

 one hexagonal, the height and breadth of each being about equal; 

 radials a little broader than high, slightly larger than the basals, nearly 

 hexagonal, the upper or outer angle of each hexagon being truncated 

 and concavely excavated for the reception of the base of the tirst 

 brachial, though the articulating scar of each radial does not occupj' 

 more than one half of the entire diameter of the plate: tirst brachials 

 subquadrangular in outline and about twice as broad as high: second 

 brachials five sided, much broader than high, their bases broad, their 

 lower or inner sides shoi-t and slightly divergent, and their upper and 

 outer sides shallowly concave : be3'ond this the characters of the arm 

 plates are unknown. Anal plates two, both five sided with unequal 

 sides, the first or lowest one about as broad as high, with a narrow 

 base, and the second or upper one broader than high, with a broad 

 base. Dome plates unknown : surface of the calyx smooth. 



Approximate dimensions of the onlj' specimen collected, which is a 

 little distorted : height of the calyx, up to the base of the first brachials, 

 six millimetres; greatest breadth of the calyx, eight mm. 



