58 PEOCEEDINGS OF THE MAIACOLOGICAL SOCIETY. 



being about two-tliirds of the length of the arms, the latter being 

 about four times the length of the head. In the present specimen 

 eight arms can be seen (marked a to li in the figures, PI. IV) ; each 

 of these is furnished with a double row of booklets, which are largest 

 at about the mid-length of each ann. The arms can be grouped in pairs 

 according to their size, although their exact order cannot be definitely 

 ascertained. The pairs seem to be as follows : a&,h, h&g,c&f, 

 d & ff ; and so far as can be made out from this example, the arms 

 appear to have been arranged in the order of the lettering. Each of 

 the arms a, h is about 38 mm. long and 5 mm. wide, and furnished with 

 two rows of booklets, about nine or ten in each row. The pair b, g 

 appears to have been the largest, nearly 85 mm. long and about 10 mm. 

 wide, thickest at the proximal end, slowly tapering towards the distal 



Fig. I. Fig. II. 



Enlarged views of the central portions of the figures on Plate IV. The lettering is 

 the same for all the figures. 



extremity, and furnished with two rows of booklets, of which there 

 were probably fourteen or fifteen in each row. The pair c, f is rather 

 short and broad, about 32 mm. long and 6 mm. wide, rather obtuse at 

 the distal end, and somewhat thickly studded with booklets, there being 

 two rows of nine or ten booklets in each. The pair d, e is about 55 mm. 

 long, and 6 mm. in greatest thickness, which is at about the mid- 

 length of the arm ; each tapers gradually towards the distal extremity, 

 and is provided with two rows of about twelve or thirteen booklets 

 apiece. 



At the base of the arms the buccal membrane is well displayed. It 

 is stellate in form, with six fairly prominent narrow radiating elevations 

 (PI. IV, Fig. 1), the central portion {p) being occupied by a mass of 

 calcite which extends for a short distance into each radial elevation. 

 These radial elevations are evidently the remains of the ligaments, 

 by means of which the membrane was attached to the bases of the 

 arms ; they are unequal in size, the two which are directed back- 

 wards (on the slab), w & n, being the largest, the two lateral ones. 



