Manchester Memoirs, Vol. iv. ( 1 9 1 1 ), No. 3*5. 3 



in each pinna. Each autozooid consists of a retractile 

 portion or anthocodia which is almost completely retracted 

 and a non-retractile basal portion usually called the calyx. 

 The length of the calyx in the fully developed pinnae is 

 about 4 mm. 



Owing to the imperfect condition of the specimen I 

 cannot venture to give a more definite statement of the 

 number of the autozooids in the pinnae. Many of the pinnze 

 are broken, and others covered with an adhesive and 

 dirty mucus, so that it requires some care to count the 

 number of the autozooids accurately. I have cleaned two 

 or three unbroken pinnae from each piece, and have 

 found the number to be constantly twelve, but it is still 

 possible that there may be some variations from this 

 number. 



The pinnae of the two sides alternate, or to use Moss's 

 expression, are arranged "en echelon." 



On the dorsal side there is a broad smooth track free 

 from autozooids, on the ventral side there is in some parts 

 of the rachis a narrow smooth track, but at the free 

 extremity the pinnae of opposite sides overlap ventrally. 



The pinnae of each side, when fully developed, slightly 

 overlap the pinnae immediately above them, so that the 

 distance between the pinnae is from 3'5-4 mm. In a 

 portion of the middle of the rachis, 50 mm. in length, I 

 have counted 11 pinnae. 



In the rough sketch of the specimen forwarded to 

 Professor Bell, the rachis occupies approximately two-thirds 

 of the total length, and from this a rough estimate may 

 be made that there were probably about 450 pinnae on 

 each side. 



In each pinna the outlines of the calices can be seen 

 extending to the base, but they are firmly bound together 

 by a web, in which cellular cords and canals can be seen 



