APPENDIX. 



Containing fuller descriptions and accounts of the habits of the 

 species described in the earlier pages of the work, which were 

 printed before Dr. Johnston's death. 



Order I. TURBELLARIA, Ehrenherg (page 2). 



Of this Order M. E. Blanchard, a very competent critic, remarks : — 

 "En outre, cette classe est composee d' elements heterogenes, comme 

 I'ont reconnu tous les zoologistes. Aussi, M. Siebold, tout en I'adopt- 

 ant, I'a-t-il reduite aux deux groupes des RhabdocUes et des Pla- 

 naires. Les Nemertina, que certains zoologistes considerent encore 

 comme devant former un groupe dans le voisinage de celui des Pla- 

 nariees, me paraissent, au contraire, s'en eloigner considerablement ; 

 et M. Siebold a meme cru devoir plutot les rattacher aux Annelides, 

 ce qui, du reste, ne saurait etre admis ; mais cet exemple montre 

 combien jusqu'a present les caracteres de tous ces animaux out e'te 

 peu etudies et mal definis. Les Gordius et les Nais, que M. Ehren- 

 berg range aussi dans sa classe des Turbellaria, ont cte reconnus par 

 tous les zoologistes, je crois, sans exception, comme appartenaut les 

 premiers aux Hebninthes, et les derniers aux Annelides.'' — Ann. des 

 Sc. nat. vii. 100 (1847). 



Convoluta paradoxa (page 16). 



I had named this species Planaria macrocephala because of the 

 bluntness of its head, for the enlarged end is the anterior one, a fact 

 which the mere examination of the figure would never resolve, since 

 the part is distinguished by none of its usual appendages or organs ; 

 it has neither mouth, eyes, nor tentacula. But all unfurnished as it is, 

 there is no species of its genus that I have met with that excels it in 

 activity. Ever-restless, it glides along the surface of the vessel with 

 great celerity, varies its course with ease, and sometimes leaving the 

 bottom, it swims in the bosom of the water, but with a tardier pace. 



