38 CANADIAN FOSSILS. 



length of cup in the specimen examined, two lines, breadth at base of 

 free rays, the same ; length of free rays, one inch and one-eighth ; 

 thickness upon the back below the first sub-division, about one-fifth 

 of a line. At three- fourths of an inch below the base of the cup 

 there are five joints of the column to one line in length. The two 

 arms visible in the specimens bifurcate at the fourth free joint, and 

 three times again at varying distances above. Only one side of the 

 specimen can be seen, yet the characters of the cup and arms are so 

 similar to those of the last species that there can be little doubt of its 

 generic affinities while the globular joints of the column and the thin 

 sharp backed arms are characters sufficient to separate them speci- 

 fically. 



Explanation op Figures. Platb III. 



Figure 2a. Posterior side of a specimen, 

 " 2b. Portion of the column, enlarged. 



Locality and formation. — Upper part of the Trenton limestone, near 

 the Toll-gate, St. Lawrence Street, Montreal. 



Dendrocrinus proboscidiatus, Billings. 

 Plate III. Figures 3a, 3b, 3c. 



(D. PROBOSCIDIATUS, Report Geological Survey of Canada, 1856, page 267.) 



Description. — Cup, small, conical sub-pentagonal; proboscis, 

 enormously large in proportion to the size of the cup ; column, 

 pentagonal with raised edges along the five angles, and with concave 

 faces between, composed of very thin joints, twenty-four in the 

 length of two lines ; the arms are thin and sharp on the back. In a 

 specimen, the crushed cup of which is three lines in length, there is 

 a proboscis attached, sixteen lines in length ; the portion seen is of a 

 very remarkable structure ; it is composed of four vertical rows of 

 small plates, with a strong central keel running up each row, from 

 either side of which projects, nearly at right angles, a pair of short 

 ridges to the outer side of each plate, giving to the surface the 

 appearance of several small rope ladders side by side, as in the 

 rigging of a ship. This peculiar style of ornament is well shewn 

 in the figures of D. longidactylus (Hall), Pal. N. Y., vol. 2, fig. 7a, 

 plate 42, but the pattern is somewhat different ; in that species the 

 transverse ridges diverge from each other at an angle of about 45 



