— 19 — 



related, but there is not the variet>' 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 

 Societe Malacologique de Belgique. Tome IX, 1874). M. Ru- 

 tot believed that these spicules belonged to two sponges 

 merely, though there is no 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. III. 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 



