371 



numerous tubes, whose walls are made of triradiate spicules of one size 

 only, braced by acerate spicules, sometimes of great proportionate length. 

 The most remarkable form of this genus is Leucosolenia lacunosa, deriving 

 its specific term from its numerous lacunae. It grows upon a pedicel 

 producing an ovate development ; it is unique in character, and quite 

 unmistakable when discovered. L. contorta is common, as it is found 

 parasitic on small alga) ; none the less is it to be esteemed by the student. 

 L. coriacea is a creeping form, and in no way pipe or tube-like. The others 

 are interesting, and conform to the character of the genus. 



Leuconia is in structure divided from the last by its not having its triradate 

 spicules of the same size. Indeed, the prevalence of large forms of this, 

 particularly note it out for observation as a peculiarity. L. nivea, a coat- 

 ing form, is its essential type. Lastly, Leucogypsia (white earth) a small 

 species, sessile, and not symmetrical, has its triradiate skeleton bound by 

 short, strong, fusiform, acerate spicules, enough in itself to distinguish this 

 from all its congeners. I have found it at Torquay (L. Gossei) amongst 

 roots of Laminaria, the fertile source of so many species of various kinds, 

 that have come into my hands. I therefore recommend the gathering of such 

 when found encrusted with organisms, as a handy collector of relics of sea- 

 life. 



The student must be warned against certain objects often found, and 

 which simulate the sponges. One of these is an ascidian forming a stellate 

 crust of white colour. The ovisacs of one of the Natica have been mis- 

 taken, and may be again, for a sponge, as also the horny base which is 

 seen with some of the zoophites, such as Antennularia. The spicules of 

 sponges are well represented and described in Vol. i. of Dr. Bowerbank's 

 " Spongiadse," and the general forms of British sponges in Vols. iii. and iv. 

 of that work. 



The following objects were exhibited in the library: — 



Diatom, Bacillaria paradoxa (living) . . . Mr. F. W. Andrew. 



Foraminifera from the Red Chalk, Yorkshire... Mr. G. Bailey. 



Section of stem of Begonia ... ... ... Mr. G. B. Mainland. 



Lophopus ... ... ... ... ... ... Mr. T. J. McManis. 



Diatoms, Triceratium decangulatum, &c. ... Mr. H. Morland. 



„ Aulacodiscus Hartianus ... ... Mr. E. M. Nelson. 



Limnias ... ... ... ... Mr. C. Le Pelley. 



Sponge, Geo dia Barrettii ... ... ... Mr. B. W. Priest. 



Volcanic ash from Langdale Pike ... ... Mr. G. Smith. 



»» » 



Felsite from Canock Fell 



Diatom, Actinogonium septenarium. Var. ... Mr. G. Sturt. 



Spirogyra orbicularia, in conjugation... ... Mr. J. J. Vezey. 



Sponges, various... ... ... ... ... Mr. J. G. Waller. 



Cordylophora lacustris ... ... ... ... Mr. A. Weldy. 



Attendance — Members, 63 ; Visitors, 10. 



