564 Transactions of the Society. 



small enlargement conico-cylindrical in shape, with a globular or 

 convex base towards the end of the spicule. (Fig. 7.) 



A second spicule of the same shape, with enlargements of the 

 axial canal, is ^-J-^ inch long and ytVo i^^ch broad (Fig. la). There 

 is a great enlargement at each end and a smaller one in the middle 

 which is joined to one of them by a normal axial canal, and to the 

 other by a globular and minute enlargement. The enlargements 

 are very elegant in their outlines, being long cylindrical cones with 

 rounded bases, or with the base with two curves. A third spicule 

 has three enlargements of the axial canal of nearly equal size and 

 they are united by short and very slightly enlarged tubes. The 

 enlargements are conico-cylindrical, and the broad bases of two are 

 towards each other (Fig. 7&.) 



Another group of these spicula having the same shape and 

 dimensions has the specimens with the axial canal open at one or 

 both ends. In one form the open canal is slightly enlarged, and 

 then it contracts to the normal breadth, then it expands rapidly 

 and again contracts gradually, terminating in a long, normal axial 

 canal. This ends in a small tear-shaped enlargement leading to a 

 canal which is open at the end of the spicule. (Fig. 7c.) 



A second spicule of this type has its ends widely open, leading 

 to great cylindrical enlargements which occupy nearly all of it. 

 They have rounded extremities, which are connected by a slightly 

 enlarged tubular canal. In this instance there is but a very thin 

 film of siliceous covering, over the expansions. (Fig. Id.) 



Lastly, a fractured -specimen has an open axial canal at the 

 remaining end, and this enlarges into three small elongate cavities 

 leading to a large one which gradually occupies the whole inside ; 

 excessive thinning of the spicule at last determined its fracture. 

 (Fig.le.) 



A large form of this spicule is fractured at both ends and it lies 

 with its curvature placed vertically. There is a slight widening of 

 the axial canal in the middle of the spicule, and on either side 

 there is a series of enlargements of considerable width, the last 

 being broken across by the process of thinning of the wall. On 

 one side of the central portion, there are four enlargements and 

 part of a fifth, and on the other there are three and part of a fourth. 

 All are long, broad, and have more or less conoid outlines with 

 rounded bases. (Fig. 7*.) 



Cylindrical-fusiform, blunt or sharp pointed, straight spicula 

 are rare in the deposit. In one with blunt ends (Fig. 8) there is 

 a very large axial cavity ending in a normal axial canal, which, 

 however, enlarges slightly in one part of its length. This spicule 

 is open at the end near to the large cavity, and the axial canal 

 ends very close to the other termination. 



Fig. 8a is a magnified view of a sharply pointed spicule which 



