196 Linmsan Society. 



Yorkshire, and oi Equisetum Drummondii, Hook., from Winch Bridge, 

 Teesdale ; both species gathered for the first time in England. 



William Borrer, Esq., F.L.S., presented specimens of Leersia ory- 

 zoides, Sw., discovered by himself in Sept. 1844, fringing the ditches 

 in Henfield Level, Sussex. 



Read, a memoir " On the Medusa prohoscidalis of Forskahl." By 

 Prof. Edward Forbes, F.L.S. &c. 



The author met with this Medusa on the coast of Asia Minor, and 

 communicates the result of his examination of its form and structure. 

 The umbrella of the specimen described measured tvi^o inches and 

 three quarters in diameter, and was perfectly hemispherical and trans- 

 parent. The margin had a pink border, from which sprung at regular 

 intervals six very long extensile tentacula, at the base of each of 

 which is a minute ocellus. Opposite and above the origin of each 

 of these tentacula, and on the inner surface of the bell, is a phylli- 

 form space, of a different tissue from the rest of the umbrella : these 

 have hitherto been described as stomachs, but are in reality the ova- 

 ries ; through the centre of each runs a narrow canal, and between 

 each in the interspace are seven lanceolate, truncate markings. From 

 the centre of the inferior surface springs a proboscis or peduncle, 

 four inches in length, down which the gastric vessels run ; this pe- 

 duncle is marked by six longitudinal bands of pinkish contractile 

 tissue ; at its extremity it bears a hollow bell-shaped body, bordered 

 by six triangular lips : tlie cavity of this is the true stomach.; the 

 gastric vessels spring from it, and go to open into a circular vessel 

 surrounding the margin of the umbrella. 



The author's observations, demonstrating the true position of the 

 stomach and reproductive organs in this animal, do away with the 

 anomalous definition formerly given of the genus Geryonia, to which 

 it belongs, and require the substitution of a new generic character, 

 which may be expressed as follows : — 



Geryonia, Esclischoltz. 



Umbrella hemisphserica :" ovaria plura phyllifonnia in circuitu disci : 

 cirrhi marginales distantes : ocelli nudi: peduncuhis elongatus, pyra- 

 midatus, ventricuhim parvum in extremitate gerens; ore lobato, fim- 

 briato. 



Type, Geryonia prohoscidalis. 



November 19. — R. Brown, Esq., V.P., in the Chair. 



Read a Note by William Griffith, Esq., F.L.S. &c., to his paper 

 *' On the Ovulum of Santalum, Osyris, Loranthus, and Viscum" 

 printed in the last Part of the Society's Transactions. 



In this note Mr. Griffith states, that " having had opportunities, 

 after my revised examination of Santalum album, of examining a 

 Malacca species of Osyris (belonging to a section characterized by 

 a quinary number of parts of the flower, a less tendency to separation 

 of the sexes, and habit), I find full grounds for believing that the 

 mode of development of the ovulum of Osyris napalensis is altogether 

 like that of Santalum album, the only difference being the unim- 



