Observations on Notomnuda WerneckU. By Prof. Bdhiani. 535 



pharyngeal bulb, the salivary glands, the oesophagus, the stomach, 

 the gastric glands, and the intestine. 



On the median line of the buccal vestibule, between the rota- 

 tory organ and the pharyngeal bulb, but nearest to the latter, is a 

 longitudinal slit whose sides are so exactly in contact that it 

 requires great attention to discover them. It properly represents 

 the huccal aperture (Fig. 6, fco), which has been hitherto completely 

 overlooked by observers, the cavity which we have called the buccal 

 vestibule being commonly described as the mouth. When the 

 vestibule is more or less shut, the mouth is hidden by the lips of 

 the vestibule (Fig. 7, I'), but when open it is visible by the retrac- 

 tion of the lips (Fig. 6, ho). 



The ijharyngeal hulb, or mastax of the English naturalists, is a 

 rounded pale mass, of homogeneous appearance, and without trace 

 of the striae caused by muscular fibrillae so visible in several other 

 Notommata (Figs. 3, 6, 7, ph). This absence of striation, an 

 index of a feeble development of the contractile elements, is 

 in keeping with the almost rudimentary condition of the jaws 

 which the pharyngeal muscles move. The masticatory apparatus 

 is far less complicated than in the greater part of the other species 

 of the same genus. It most resembles N. vermicidaris as 

 figured by Dujardin.* Each jaw is composed of the small lateral 

 branch called by Dujardin sca][)us,\ which is articulated at its extre- 

 mity with a small horizontal piece bent inwards, which constitutes 

 the tooth proper {acies of Duj.). This tooth rests on a single 

 median part, bifurcated anteriorily, which forms the support (ful- 

 crum of Duj.).| 



Ehrenberg knew the extreme simplicity of the masticatory 

 apparatus of N. Wernechii, through the drawings of Werneck, 

 and remarked that the jaw had only one tooth. The feeble 

 development of this apparatus is probably acquired, secondarily, by 

 its parasitic hfe, and when the food (the vegetable plasma) is soft 

 and easily divided, as the stronger and more complicated jaws 

 of the free species are adapted to seize and eat hard and resisting 

 substances. 



At the posterior part of the pharynx are observable a pair of 

 small, glandular, ovoid organs, disposed symmetrically, which are 

 fixed by an attenuated extremity to the posterior edge of the 

 pharyngeal bulb. From their forward position in the digestive 

 tube, I consider them salivary glands, opening into the cavity of 

 the pharynx by the attenuated part which represents the excretory 

 passage. In the young individual these organs are comparatively 

 large (Fig. 2, gs)\ in the old they are very small and driven into 



* ' Histoire Naturelle des Infusoires,' 1841, pi. xxi. fig. 7. 

 t These pieces constitute the nudlci of Ehrenberg. 

 X This is the incus of Ehrenberg. 



