1 U INTEODUCTION. 



In the Quebec series of Canada there are numerous fossils which have been 

 referred to sponges by the late Mr. Billings ; but as nothing definite is yet known of 

 their minute structure, the true character of these fossils remains doubtful. They 

 have been placed in the genera Archoeocyathas, Calathium, Eosporxjia, E/iabdarki, 

 and Trachyuin. 



Silurian S//sf,em.— Sponges are by no means generally distributed in Silurian strata, 

 though they are not uncommon in beds of the Niagara series in North America and 

 in strata of corresponding age in the Silurian basin of the Baltic. They are also 

 present in the Boulder drift beds of North Germany. The order Monactinellidee is 

 here represented for the first time by the genus Climacospongia, the Lithistidfe by 

 Aulocopium, Hindia, and the somewhat doubtful Aulocopina. Belonging to the 

 Hexactinellidie are the genera Protachilleum, Astylospongia, Palceomanon, and the 

 remarkable genus Astrceospongia. The genus Amphispongia from the Upper Silurian 

 of the Pentlands is a dubious form, and also the genus Brachiospongia from the 

 Niagara group of North America. 



Devonian System. — Very few sponges have as yet been discovered in rocks of this 

 age. To the Monactinellidte belongs the genus Lasiocladia from Belgium. No 

 member of the Lithistidse has yet been discovered in this division. The Hexac- 

 tinellidae are represented by Astrceospongia from Belgium and Illinois, and by the 

 peculiar genus Dictyophyton from the Upper Devonian strata of New York. Calca- 

 reous sponges belonging to the genus Peronella also appear here for the first time. 



Carboniferous System. — From the Carboniferous Limestone of Scotland the Monac- 

 tinellid genera Pulvillus, Baphidistia, and Beniera have been described by Mr. 

 Carter, as well as the Hexactinellid Hyalostelia and Ilolasterella. Detached spicules 

 of Lithistid and Tetractinellid sponges also occur. Lately Steinmann has described 

 three genera, Sollasia, AnihJysiphonella, and Sebargasia, of the family of the Phare- 

 trones, from the Carboniferous of Spain ; but as no spicular structure has been pre- 

 served, the character of these forms is at present uncertain. 



Permian System. — No well-ascertained sponges have been met with in this division. 

 According to Prof. Zittel, the genus Bothroconis, King, might prove to be a Hexac- 

 tinellid, and Eudea tuberculata, King, a calcareous sponge ; but these forms have 

 not come under my notice, and, judging from the figures given of them, their true 

 characters appear to be very uncertain. 



Triassic System. — No siliceous sponges have been recorded from this division, but 

 in the St.-Cassian beds in the Tyrol numerous calcareous sponges are present. As a 

 rule, the fibre of these forms does not show any minute structure, and the sponge- 

 character of some of tliem is very problematic. These St.-Cassian forms have been 

 included in the following genera — Eudea, Colosptongia, Verticillites, Celyphia, 

 Himatella, Pej'onella, Corynella, Myrmecium, and Stellispongia. • 



JAassic System. — It is only within the present year that fossil sponges of this 



