1.8*79.] Physiology and Histology of Convoluta Schultzii. 453 



was purified by repeated solution and recrystallization in absolute 

 alcohol. With PtCl 4 it yielded a precipitate, which was kindly analysed 

 for me by Dr. Magnier de la Source^ and found to be the platino- 

 chloride of methylamine : however, it is very probable that the volatile 

 alkaloid was really more complex, but broke up in the distillation. 

 The subject would repay the attention of a chemist. Trimethylamine 

 has been obtained from many animal sources, and the production of 

 this, or some nearly allied body, in such remarkable quantity by 

 Convoluta seems to be a protective specialisation. 



The ash of the Convoluta contains iodine, another analogy to the 

 alga3. 



As the Drosera, Dioncea, &c, which have attracted so much atten- 

 tion of late years, have received the striking name of Carnivorous 

 Plants, these Planarians may not unfairly be called Vegetating 

 Animals, for the one case is the precise reciprocal of the other. Not 

 only does the Dioncea imitate the carnivorous animal, and the Con- 

 voluta the ordinary green plant, but each tends to lose its own normal 

 character. The tiny root of the Drosera and the half -blanched leaves 

 of Pinguicula are paralleled by the absence of a distinct alimentary 

 canal and the abstemious habits of the Planarian. 



It still remains to ascertain the behaviour of other green animals, 

 and I hope to begin with Hydra and Spongilla* as soon as the season 

 permits. 



Part II. — Histology. 



The general characters of the animal have been already given by 

 Schmidt, and I need only add that I have succeeded in making out 

 the mouth, which lies, as usual in this genus, a little way behind the 

 otolith . It is not a mere transverse slit, but is surrounded by a lip 

 capable of slight protrusion, which evidently corresponds to the pro- 

 trusible pharynx of higher Planarians. When feeling its way the 

 animal has a curious habit of sharply retracting the terminal point of 

 the anterior ends of the body, the head thus becoming bilobed, with a 

 central depression. Each lobe becomes a sort of temporary tentacle, 

 and these may be compared with the blunt permanent head lobes of 

 allied forms. So too the animal " when extremely contracted " throws 

 its smooth dorsal integument, not into irregular wrinkles, but into 

 rounded papillae, which remind one of the permanent dorsal papillae of 

 other Planarians. 



I will first notice an interesting point in the histology of the ciliated 

 ectoderm. In teased preparations, kept cold, the ciliated cells often 

 become amoeboid, some of the cilia changing into slender finger-like or 

 stout fusiform pseudopodia. These often retain their curvature parallel 



* Sorby has suggested the probably partial vegetal mode of life of S. viridis, and 

 resultant analogy to Dioncea. (" Quart. Journ. Micro. Sci.," 1875, p. 51.) 



