134 BR A. MILNES MARSHALL ON THE 



3 mm. above the uppermost polyps, ending in an abruptly truncated and 

 evidently broken extremity. At the lower end the fracture appears to have 

 occurred about the junction of stalk and rachis, but the fleshy sarcosoma has 

 been stripped off the lowermost 8 mm., leaving this part of the stem bare, and 

 rendering it impossible to localise exactly the seat of fracture. The stem is 

 quite as brittle as that of Virgularia, so that there can be little doubt that the 

 cause of fracture is the same in the two cases. 



The entire specimen is of a pale yellowish-white colour, but has become a 

 good deal discoloured in parts, apparently from the action of the spirit in which 

 it was preserved. 



The polyps (figs. 17, 18, and 19) are arranged in pairs along the sides of the 

 rachis, each pair being embraced at its base by the fan-shaped plate of cal- 

 careous spicules k, so characteristic of the family Stylatulidce. The pairs of 

 polyps are not inserted opposite one another, nor do they strictly alternate'; but 

 those- of the left side are situated a little further forward, nearer the upper end 

 of the rachis, than the corresponding pairs of the right side. 



The intervals between successive pairs of polyps on the same side of the 

 rachis (fig. 17) gradually increase in passing upwards. At the lower end of the 

 specimen the successive pairs are almost in contact with one another, but in 

 passing upwards they move further and further apart, the intervals attaining a 

 maximum a short way below the upper end of the specimen, above which point 

 they decrease slightly, the polyps themselves also becoming smaller. 



The characters and relations of the fan-shaped spicular plates are well shown 

 in figs. 18 and 19. Each plate is triangular, with the apex directed downwards 

 and inserted into the rachis, and with its free upper edge surrounding the base 

 of the pair of polyps to which it belongs. The plate is formed by the fusion of 

 a number of radiately arranged spicules, of which the more deeply placed ones 

 are smaller and completely fused together, while some of the more superficial 

 ones are much larger, and not so closely fused. One of these large spicules is 

 represented in fig. 21 ; it is widest near its lower end, and gradually tapers 

 upwards to a point, which (figs. 18 and 19) projects freely for a short distance 

 above the upper edge of the plate. These large spicules may attain a length 

 of 23 mm. and width of 015 mm. From the apex of the spicular plate a 

 number of smaller rod-like spicules (fig. 18) are continued for a variable distance 

 down the rachis. 



The two polyps of each pair have their bases, which are covered by the 

 spicular plate, fused together so as to form a rudimentary leaf. Above the 

 level of the top of the spicular plate they are, however, completely free from 

 one another. Of the two polyps, the dorsal one is always slightly smaller than 

 the ventral one in accordance with the general rule among Pennatulida. The 

 dorsal polyps of corresponding pairs are separated from one another by but a 



