Mr. F. M'Coy on some new Mesozoic Radiaia. 407 



This delicate little species has a very singular aspect, and dif- 

 fers from its congeners in the hands not continuing as thick main 

 branches, giving off comparatively thin fingers from one side, 

 but both hands and fingers dichotomizing into perfectly equal 

 branches. 



I have examined portions of eight heads, some nearly perfect, 

 with their columns and side-arms, on a slab of lias shale from 

 Whitby. 



{Col. University of Cambridge.) 



Peniacrinus Goidfussi (M'Coy). 



Sp. Char. Column pentagonal, joints alternately thicker and 

 thinner, or three thin between each pair of thicker joints, ar- 

 ticulating by five oval, prominent, finely crenated ridges, the 

 intervening spaces much depressed; auxiliary side-arms large, 

 flattened, of elliptical joints, five arising from every thick co- 

 lumnar joint (one from each side), the long axis being attached 

 vertically ; pelvic joints large, cuneiform ; first costals hepta- 

 gonal, twice as wide as long, flattened (not produced into a 

 cone downwards), each having a prominent tubercle in the 

 centre, adhering laterally by only a short portion of its mar- 

 gin ; second costals horseshoe-shaped ; scapulae cuneiform, as 

 long as wide ; from which two arms arise, of eight or nine 

 joints, the last being cuneiform and supporting two hands, the 

 inner of nine and the outer of fourteen or fifteen joints, the 

 last cuneiform and giving off a lateral finger, and after four- 

 teen or fifteen joints more another (total number of fingers 

 unknown, but small). 



In the great number, size, and mode of insertion of the auxi- 

 liary side-arms this agrees with the P. Britannicus (Schlot.), (P. 

 Briareus, Mill.), but differs in its small size, broad oval penta- 

 petalous markings of the columnar joints, and from that and all 

 allied species it strongly differs in the first costals not being pro- 

 longed into a cone down the sides of the column. 



There are clearly two species confounded by Goldfuss under 

 the name P. scalaris, one of which, figured on the 60th plate of 

 his * Petrefacten,' is much allied to this ; the other figures on 

 pi. 52 of the same work differ considerably, but agree with nu- 

 merous authentic specimens I have seen of that species from the 

 German oolites, and also with some from our lower oolite at 

 Dundry; the latter is therefore the most proper type of his 

 species. 



Marlstone, Gloucestershire. 



{Col. University of Cambridge.) 



