— 31 — 

 Geodia? coronata n. sp. 



(Plate II fig. 6, 7, S.) 



\'eiy robust spicules with a conical shaft, inflated at the 

 upper end, and from thence gradually tapering to a point. 

 Immediately on the inflated shoulder of the shaft, or with 

 a ver>' short intcr\'cning neck, are placed from 3 to 6 relatively 

 very short, pointed rays, at a more or less open angle with 

 the shaft. The shafts of these spicules arc mostly straight, 

 but in one example the lower end is curved. The rays, both 

 of the simple and compound fonns arc very equal in size, 

 and the compound rays bifurcate so close to the head of 

 the shaft, that, in many instances, they appear to spring from it 

 independently. As in the previous species , one or all of 

 the primary ra>s of a spicule may become bifurcated. The 

 total length of a small .spicule (fig. 8) is 2,25 mm.; width 

 across the head 0,45 mm.; diameter of shaft 0,27 mm. The 

 length of an average spicule is 4,05 mm., the width of the 

 rays 0,315 mm.; and of the shaft 0,45 mm. The.se spicules 

 are somewhat rare. ^ 



From the peculiar arrangement of the rays, I propose 

 to name this spicule Geodia .' coronata. Similar spicules are 

 present in the Chalk of the North ofL'eland (Wright: op. cit. 

 PI. II fig. 13a, 13b). 



Geodia? Wrightii n. sp. 



(Plate II fig. 12). 



Robust simple trifid spicules with an elongated shaft 

 gradually tapering from the summit to the pointed extremity, 

 the arms straight and directed forwards at angles varying 

 between 35" and 60" with the shaft. The shaft furnished 

 with from 10 to 14 ring-shaped expansions, extending at 

 regular intervals from each other, from the summit to two-thirds 

 or three-fourths of its length, the lower portion of the shaft being 

 smooth. Each of the arms has also 4 to 6 similar rings. In some of 

 the smaller .spicules the rings of the shafts and arms are b)- no 



