EXTRACTS AND ABSTRACTS FROM FOREIGN JOURNALS. 155 



Genus TRACHELOMONAS. 



Eye present ; lorica a closed case, or urceolate, not rostrate, or pro- 

 vided with a neck. 



Three species are known : two are of a green, one of a dark brown 

 colour. 



(Sfytractsl arrtJ &fjgtract2( from 



[From Valentin's Repertorium, 1 84 1 .] 



Unger on Chrysomyza Abietis. Under the name of Chrysomyza 

 Abietis is described by Unger, in F. J. F. Meyen's Jahresbericht, &c., 

 for 1839, a peculiar exanthem of the Fir. He states, that the 

 leaves assume a yellowish red colour, owing to the presence of Dro- 

 minent, linear, rusty brown spots, without being themselves otherwise 

 swollen. The yellow colour is more or less diffused on the upper side 

 of the leaf ; but on the under side, besides this diffused colour, there 

 are found one or more rusty brown spots, placed in a double row on the 

 sides of the projecting leaf-veins. The situation of these spots corre- 

 sponds, nearly always, with that of the Stomata. In the young state 

 they are more opaque, and become when older more transparent, and 

 more denned. The degeneration consists in a multitude of elongated 

 vesicles, which are confined in a mucoid matrix containing granules, 

 sometimes coloured, and sometimes colourless. This matrix forms an 

 outer covering to the vesicles, and gives them occasionally a varicose 

 appearance. They contain a yellowish grumous matter. The colour is 

 not dissipated by boiling in alcohol. The disease commences in the 

 stomata, which, in place of the air, contain a granular, mucous, at first 

 uncoloured substance, which rapidly increases, becomes coloured in 

 parts, and flocculent particles are formed in it. The vesicles appear, 

 and it finally bursts through the cuticle. The course of the complete 

 development of the disease lasts above a year. Abridged, p. 92. 



Valentin on Achy la prolifera. With reference to Achy la prolifera, 

 Valentin remarks, that this mouldiness, or colourless Conferva, very 

 often recurs under favourable circumstances in animals. When occur- 

 ring on the ova of fishes, it constitutes a very powerful preventive to 

 their development, and its progress is so rapid that a single egg infected 

 with it, will in a very short time infest many hundreds, and thus 

 destroy them. He has ascertained, also, the same thing with regard to 

 the ova of Alytes obstetricans . Its action upon the eggs of mollusca 

 appears to be slower, which has been already remarked by Laurent. 

 (Rep. V, p. 44.J Valentin observed it, at all events, in a state of active 

 growth for several days upon the ova of (probably) Limnceus stagnalis, 

 during which period the embryo was in lively motion, and which did 

 not die till later. In fishes, also, as the Cyprinus nasus, when kept in 

 narrow vessels, and the water not quite sweet, he observed the same fun- 



