— 19 — 
related, but there is not the variety of Lithistid and Hexacti- 
nellid spicules as at Horstead. 
In 1873-4 Mr. Joseph Wright F. G. S. of Belfast gave il- 
lustrations of 34 different forms of spicules which he had dis- 
covered in the interior of flints from the upper Chalk Formation 
in the North of Ireland. (A List. of the Cretaceous Microzoa 
of the North of Ireland. Belfast. Nat. Hist. Field-Club Report). 
The late Dr. Bowerbank drew up a report on these spicules 
but limited himself to giving them some very long names 
and indicating the resemblances of a few of them to existing 
genera. With hardly an exception, all these Irish Chalk 
specimens are present in the Horstead flint, but the sponges 
do not seem to be anything like so well represented in the 
Irish as in the Norfolk Chalk, though the material examined 
by Mr. Wright was collected from several localities, and ap- 
pears to have been carefully searched. 
Also in 1874, M. A. Rutot described and figured nume- 
rous forms of sponge spicules from Tertiary sands of the Etage 
Bruxellien in the neighbourhood of Brussels (Annales de la 
Société Malacologique de Belgique. Tome IX, 1874). M. Ru- 
tot believed that these spicules belonged to two sponges 
merely, though there isno doubt that several different genera 
are represented. A few of these Tertiary spicules are simi- 
lar to those from the Horstead flint but so far as can be 
judged from the figures the majority of them are different 
forms. . 
In 1876 Professor Zittel figured numerous spicules which 
were from the Upper Chalk of Coesfeld and other places in 
Westphalia. (Ueber Coeloptychium. Abh. d. k. Ak. d. Wiss. 
XII. Bd. Il. Abth.) From finding many of these spicules in 
close connection with the: skeleton of Coeloptychium, Professor 
Zittel thought, previous to his later researches, that they might 
have belonged to that genus. With but few exceptions, 
the forms figured by Professor Zittel are found also in the 
