Common Eartlnvorm. 121 



terly Journal of Microscopical Science, 1864-1865, ihique 

 citata. 



See also D'Ukedem, Memoires de P Academic Royale de Belgique, 

 torn, xxxvi., 1865. 



A monograph on the natural history and anatomy of the Lum- 

 bricus Terrestris, of considerable merit, was published in Latin 

 by C. F. A. Morren in 1829, under the title ' De Lumbrici 

 Terrestris Historia Naturali necnon Anatomia Tractatus/ 



37. Common Earthworm [Lumhricus Terrestris), 



Dissected so as to show its gangliated nervous system consisting of a bilobed supra- 

 oesophageal mass and a ventrally placed nerve-cord, connected with each other 

 by commissures, which give off numerous branches on either side to the large 

 sympathetic ganglionic mass lying upon either side of the pharynx. 



The integuments having been divided down the middle dorsal 

 line and fastened out on either side, the entire digestive tract with 

 the exception of the commencement of the pharynx, through which 

 a black bristle has been passed, has been removed, together with 

 the pseud-haemal vessels in connection with it ; the segmental 

 organs, and the muscular dissepiments dividing the body into 

 compartments. The organs of reproduction have been similarly 

 removed, with the exception of the two receptacula seminis of the 

 right side, two globular white sacs which are seen opening in the 

 line of the outer rows of setae, in the intervals between the ninth 

 and tenth, and between the tenth and eleventh segments respect- 

 ively. The two lobes making up the supra-oesophageal mass are 

 pyriform, and have their broader ends apposed to each other in the 

 middle line. From their outer and narrower ends a thick nerve 

 passes off, bifurcating almost immediately, to supply the pro- 

 boscidiform and tactile anterior segment or upper lip. These 

 nerves would appear to be homologous with those given off from 

 the post-oral ganglia, and the anterior or upper surface of the 

 ganglionic mass whence they are given off to be homologous with 

 the under surface of the ventral ganglia. The cords of commissm-e 

 to the first ventral ganglion pass downwards and form the nerve 



