88 Wright — List of Irish Cretaceous Microzoa. 



and Planorbulince with less regular holes. M. Vanden Broeck, of Brussels, 

 has lately discovered a Lageniform ' porcellanous' Foraminifer with a regu- 

 larly cribrate or latticed shell. Thus in both divisions of the Foraminifera 

 we have open-chambered shells, analogous to the basket-like structure of 

 the siliceous Polycystina (Radiolaria). How far these may be taken as 

 indications of another, or other divisions of the Rhizopods, further research 

 will show." 



122. Fragments of tubular branched forms more or less aculeate near to the 

 so called Dentalina (?) aculeata of D'Orbigny. My friend Professor T. 

 Rupert Jones proposes to distinguish this simple, calcareous, subsegmented , 

 branching, Nodosarian form by the "generic" name Ramulina (from 

 "ramulus," a little branch) ; the "species" above mentioned, which is 

 common in the French and British chalk standing as Ramulina aculeata 

 (D'Orb.), and our Irish form, which differs from D'Orbigny's in being 

 smooth, as Ramulina l^vis, gen. et sp. nov. Jones, see PI. III. fig. 19. 

 Rather rare. 



123. Ramulina brachiata, sp. nov. Jones, see PI. III. fig. 20. Very rare. 

 Professor T. Rupert Jones says of this form that its nearest known analogue 

 in external form among Protozoa is perhaps Dr. Wyville Thomson's 

 Ccelosphara tubifex, a peculiar Sponge from the North Atlantic. Still the 

 fixed position of the tubes and the general aspect of the organism are 

 against the probability of these Microzoa being closely allied. 



SPONGE SPICULA.* 



SKELETON-SPICULA. 



124. Acerate spiculum, PI. II. figs. I and 2. This form is found abundantly 

 in the Halichondroid sponges both recent and fossil, but it is generally very 

 minute. The same form also prevails to a great extent in the skeletons of 

 many species of Tethea and Geodia, in both of which these spicula are of 

 about the same size and form as those found in the Chalk, and I have no 

 doubt that they are from fossil species of one or the other of these genera. 

 Frequent. 



125. Attenuato-acuate spiculum ; an abnormal form, PL II. fig. 3. Very rare. 



126. Moniliform attenuato-acuate spiculum, PI. II. fig. 4. Rather frequent. 



* I am indebted to J. S. Bowerbank, LL.D., F.R.S., for the following report on the 

 Sponge spicula. 



