4 Bulletin 23 30 



others much smaller and plain. The trunk tapers upwards and 

 is deeply grooved along the fusion of the rays and which also ex- 

 tend into the branches. Armlets given off at every 3d, 4th or 

 5th brachial plate, those of the branches at each 4th brachial plate : 



Regular interradials 1, 2, 3, and others above, more or less 

 hexagonal in shape and highly ornamented. The plates rapidly 

 decrease in size on passing upwards towards the ventral surface 

 and the shape varies. 



Observations : 



The specimen was found at the McGraw or University quarry, 

 which is situated in the center of the Ithaca formation of the Por- 

 tage series. It has been highly productive of rare and interesting 

 forms. 



Melocrinus williamsi, n. sp. Plate 6, Fig 3. 



Specimen about medium size. Dorsal cup higher than wide. 

 Arms five, biserial. 



Plates tumid, with the centers of each, supporting a conspicu- 

 ous spiniferous node. This applies not only to the plates of the 

 dorsal cup, but also to the plates of the vental surface and of the 

 anal tube. The centers of the radials and brachials are connect- 

 ed by a ridge like elevation, which commencing on the basal 

 plates follows up through the radials and brachials, dividing the 

 dorsal cup into five equal fields. The interradials above the first 

 (1st) have their centers connected by a low ridge, which passes 

 from one plate to another, but is much less pronounced. The 

 spiniferous node in the center of the radials and of the first (1st) 

 interradial plates is surrounded by a circle of low bead-like ele- 

 vations. 



Basals four (4) strongly tumid, those shown on the specimen 

 pentagonal in shape. Radials twice as large, those shown on the 

 specimen pentagonal in shape and as wide as high. Costals two 

 (2), of nearly equal size, but much smaller than the radials. 

 First (1st) costal hexagonal, second (2nd) heptagonal in shape 

 and both slightly higher than wide. Distichals 1x10 borne on 

 the inner surface of the second (2nd) costals, pentagonal in 

 shape and slightly higher than wide. 



