INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 725 



Nemertines, provided with a number of lateral diverticula. The body 

 is iu vested by a well-ciliated simple epithelium, in which there are 

 dark pigment granules, but the rod-like structures, so commonly 

 found in the integument of allied forms, are here completely absent. 

 The dermo-muscular tube is formed of an external circular, and an 

 internal longitudinal layer ; the whole of the ccelom is filled with 

 connective tissue. The testes and ovaries are fouud, as they are in 

 some other rare cases among the Nemertinea, in the same individual. 

 The proboscis has exactly the same structure as in the other Enopla, 

 but, as in Malacobdella, it opens into the jiharyngcal cavity, and not iu 

 front of it or above it, as in most of these forms. The nervous system 

 is of the ordinary and typical form. 



All the points already regarded point to the general similarity of 

 Geonemeries with the rest of the Nemertinea, but there remains to be 

 noted a special organ of very curious character. At the anterior end 

 of the body, and dorsally to the oral aperture, there is a fine pore, 

 which leads by a short canal into a cavity which has its long axis set 

 transversely to the longitudinal axis of the body ; the canal and the 

 cavity are lined by a simple epithelium, which passes without auy 

 distinct demarcation into the investing cell-layer of the body ; the 

 cilia in the hinder portion of the enlargement being only larger than 

 in the anterior portion, and in the canal. Connected with it there is 

 another coecal sac, which is elongated in form and circular in trans- 

 verse section ; its only contents was a fine coagulum. This organ has 

 apparently some connection with the terrestrial habit of the animal, 

 but whether it is or is not sensory iu function is still an open 

 question. 



The circulatory organs are of the ordinary Nemertlne type, and 

 excretory pores still require to be observed ; they would be best seen 

 iu fresh specimens. 



Histology of Convoluta Schulzii.* — This green Ehabdocoele 

 Planarian was the subject of the observations on chlorophyll in the 

 green Planaria by Mr. P. Geddes, referred to at p. 161 (from ' Comptes 

 Kendus '), which now appears in the ' Proceedings of the Eoyal Society ' 

 with additional remarks on the histology of the animal, the general 

 characters of which have been already given by Schmidt. 



Mr. Geddes first notices 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 

 curvatm-e parallel to the unaltered cilia, and he has even seen the finer 

 pseudopodia contracting gently in time with the cilia of the same cell, 

 thus establishing a complete gradation between the rhythmically con- 

 tractile cilium and the amoeboid pseudopodium through what is really 

 a rhythmically contractile pseudopodium. Haeckel and others have 

 accumulated many instances of the transformation of ciliary movement 

 into amoeboid and vice versa, but only by Professor Lankester f has 

 the passage-form, the cilium-like pscudoijodium, been actually observed. 



* ' Proc. Roy. Soc.,' xxviii. (1879) p. 449. 

 t 'Quart. Joum. Mici-. Sci.' (1870), p. 292. 



