Messrs. Duncan & Jenkins on Pal£eocoiyne. 287 



deposits of the Atlantic with the Cretaceous formation, that the 

 vitreous sponges are more nearly allied to the Ventriculites of the 

 chalk than to any recent order of Porifera. They are inclined to 

 ascribe the absence of silica in many Ventriculites, and the absence 

 of disseminated silica in the chalk generally, to some process, pro- 

 bably dialytic, subsequent to the deposit of the chalk, by which the 

 silica has been removed and aggregated in amorphous masses, the 

 chalk flints. 



The Vitreous Sponges, along with the living Rhizopods and other 

 Protozoa which enter largely into the composition of the upper layer 

 of the chalk-mud, appear to be nourished by the absorption through 

 the external surface of their bodies of the assimilable organic matter 

 which exists in appreciable quantity in all sea-water, and which is 

 derived from the life and death of marine animals and plants, and, in 

 large quantity, from the water of tropical rivers. One principal 

 function of this vast sheet of the lowest type of animal life, which 

 probably extends over the whole of the warmer regions of the sea, 

 may be to diminish the loss of organic matter by gradual decomposi- 

 tion, and to aid in maintaining in the ocean the " balance of organic 

 nature." 



" On PalcBocoryne, a Genus of Tubularine Hydrozoa from the 

 Carboniferous Formation." By Dr. P. Martin Duncan, F.R.S., 

 Sec. Geol. Soc, and H. M. Jenkins, Esq., F.G.S. 



PaleBocoryne is a new genus containing two species, and belongs to 

 a new family of the Tubularidse. The forms described were dis- 

 covered in the lower shales of the Ayrshire and Lanarkshire coal- 

 field ; and an examination of their structure determined them to be- 

 long to the Hydrozoa, and to be parasitic upon Fenestellse. The 

 genus has some characters in common with Bimeria (St. Wright), 

 and the polypary is hard and ornamented. The discovery of the 

 trophosome and probably part of the gonosome of a tubularine 

 Hydrozoon in the Palaeozoic strata brings the order into geological 

 relation with the doubtful Sertularian Graptolites of the Silurian 

 formation, and with the rare medusoids of the Solenhofen stone. 



" On the Rhizopodal Fauna of the Deep Sea." Bv "Wclliam B. 

 Carpenter, M.D., V.P.R.S. 



The author commences by referring to the knowledge of the 

 Rhizopodal fauna of the Deep Sea which has been gradually ac- 

 quired by the examination of specimens of the bottom brought up 

 by the sounding-apparatus ; and states that whilst this method 

 of investigation has made known the vast extent and diffusion of 

 Foraminiferal life at great depths — especially in the case of Globi- 

 gerina-mud, which has been proved to cover a large part of the bottom 

 of the North Atlantic Ocean — it has not added any new generic 

 types to those discoverable in comparatively shallow waters. With 

 the exception of a few forms, which, like Glohiyarinu, find their most 



20* 



