Cyathocormus uair.ibilis n. g., n. sp. Y 



showing neither longitudinal striae nor transverse wrinkles. It is 

 almost transparent except the axial portion which is more or less 

 opaque and whitish with a tinge of pale yellow, especially near 

 the lower end. The stalk is made up entirely of the test sub- 

 stance, and no zooids, whether adult or in developmental stages, 

 are found imbedded in its tissue. 



The head has the form of a hollow cylinder open at one end 

 and closed at the other. Viewed from the side, the lateral walls of the 

 cylinder are nearly straight. At the open end the wall terminates 



I 



^/ 



^m-i. 



Text-fig. 1. Text-fig. 2. 



Diagram showing the longitudlinal Diagram showing the cross 

 section of a colong. section, of a colong. 



quite abruptly, there being no thinning out of the investing 

 mass to form a particular marginal zone (text-fig. 1). The 

 bottom of the cylinder is somewhat lens-shaped, convex on both 

 outer and inner surfaces. It is at the centre of its outer 

 or lower surface that the peduncle joins the head. Like 

 the stalk this part is entirely composed of the common 

 test and contains no zooids. Near the periphery of the basal 

 surface, however, a number of very small zooids, apparently in 

 early stages of development, are to be seen. The side wall of the 

 cylinder shows on its external surface a number (12 and 16 in the 

 two colonies examined) of very shallow longitudinal depressions 

 separating as many slightly elevated longitudinal zones. Under 

 a low power of microscope these zones are found each to be 

 composed of a double row of hexagonal areas representing the 



