Dr. M. Schultze on the Terrestrial Planarise. 1 1 



fVoui the annular muscles, which on their part enter into an 

 intimate union with the viscera, and especially with the finer 

 terminal ramifications of the intestine, so that they cannot be 

 removed without adherent portions of the latter. The condition 

 of maceration of ray Geoplana, caused by its preservation for 

 several years in spirits, facilitated the separation of the above- 

 mentioned layers, which could hardly have been effected in the 

 fresh state. 



The elements of these muscular layers are long fibres of 

 0"0006-0'002 line in breadth, homogeneous throughout, with- 

 out any distinct envelope and contents, and without traces 

 of transverse strise, exactly resembling those which I have de- 

 scribed and figured in the Rhabdoccela amongst the Turbel- 

 laria (Beitr. zur Naturgesch. der Turbellarien, 1850), and like 

 those which occur in the larger aquatic Dendrocoela. Narrow 

 and broad fibres are intermixed, the narrower ones greatly pre- 

 dominating in number ; the broader fibres divide more fre- 

 quently, and in certain cases penicillate radiations are seen 

 upon them. 



The space surrounded by the annular muscles was found to 

 be entirely filled by the intestinal canal, whilst, as has already 

 been stated, nothing could be detected, in my specimen, of the 

 secreting portions of the generative organs, which in sexually 

 mature animals will certainly push itself to a greater or less 

 extent between the ramifications of the intestine. In the 

 immediate vicinity of the genital orifice alone, the globular 

 copulative organ occupied a comparatively considerable space. 

 The commencement of the intestine was indicated by the ex- 

 ternally projecting, folded, buccal orifice of the oesophagus, 

 which was of a white colour, and formed of densely interlaced 

 narrow muscular fibres. The oesophagus is continued forwards, 

 concealed beneath the skin, and occupying nearly the whole 

 thickness of the animal, in the form of a cylinder about 1 line 

 in thickness, and 4 lines long. From it, at the extremity 

 opposite to the buccal orifice, originate three branches of the 

 intestine, one running forward in the direction of the oesophagus, 

 gradually becoming attenuated, as it gives oflF numerous branches 

 at right angles, and reaching nearly to the anterior extremity ; 

 and two passing backwards, which being bent upwards run 

 along and above the oesophagus to the posterior extremity, and 

 emit numerous branches outwards. These principal branches, 

 and the larger secondary branches of the alimentary tube possess 

 strongly muscular walls, and an internal epithelial coat of small 

 cells. As the division of the lateral branches of the alimentai-y 

 canal gradually becomes finer, the muscular layer grows propor- 

 tionately thinner, whilst the epithelial cells become larger and 



