40 Linnaan Society. 



CioNiDiuM, T. Moore in Gard. Cuinp. (nomen tantum). 



Char. Grn. Vena reticulatse. Sori semi-globosi, extra-marginales, in 

 venularum apicibus excurrentibus pedicellati; ca])siilis pedicellatis. 

 Indmia stipilatn, subcyathiformia. — Frondes bipinnatce ; soris ex 

 iitrdque phmulariim, pinnatijidarum margine promlnulis. 



Cionidium Moorii, T. Moore, /. c. 



Deparia Moorii, Hook, in Journ. of Dot. iv. p. 54. t. 3. 



Hab. in Nova Caledonia, D. C. Moore (1851). 



February 15, 1853. — R. Brown, Esq., President, in the Chair. 



Mr. Yarrell, V.P. and Treas. L.S., exhibited a specimen of the 

 Sooty Tern {Sterna fuUginosa, Lath.), a species new to Britain and 

 even to Europe, which was killed in October last at Burton-ou-Trent, 

 was preserved for, and belongs to the collection of H. W. Desvoeux, 

 Esq. 



Read an " Additional Note " to Mr. Newport's memoir on Ich- 

 neumon Atropos, Curt., in reference to the changes which take 

 place in the alimentary canal after the parasite has ceased to feed, 

 and while assuming its imago state. These changes, which are very 

 considerable both as regards form and condition, are minutely de- 

 scribed ; and every part of the canal is shown to be supphed with 

 tracheae, the trunks of which, one in each segment, passing trans- 

 versely inwards, divide into branches, which, again subdivided, pe- 

 netrate into and ramify through the structure. These, like all other 

 tracheae, are formed, as described by Sprengel, of three tissues, an 

 external membranous and an internal mucous, enclosing between 

 them a strong spiral fibre. The nature and origin of the external 

 tissue have been shown by Mr. Newport in previous memoirs ; but he 

 has since found that the ramifications of the trachea? which pene- 

 trate the structure of the canal, or of any other organ, become de- 

 nuded of this external covering, and then seem to be formed only 

 of two tissues, the spiral and the mucous, if indeed there be not also, 

 as he has some reason to think, an extremely delicate serous, or 

 basement membrane, closely adherent to and uniting the coils of 

 fibrous tissue on its external surface. The ultimate divisions of the 

 tracheae are always distributed separately, and do not anastomose, 

 ending, as noticed by Mr. Bowerbank, in extremely minute, filiform, 

 blind extremities ; and this Mr. Newport finds to be their condition 

 in all structures, in the nervous and tegumentary, equally as in the 

 glandular and muscular. These facts, the author observes, may 

 perhaps assist us to understand the nature of the injection of the 

 tracheae by M. Blanchard, and also tlie mode of nutrition in insects ; 

 the ultimate branches of tracheae in the tissues of the alimentary 

 canal operating, possibly, as absorbent structures, and inducing the 

 chylific fluid elaborated around them to flow, in its transit outwards, 

 along the channels formed by their loose peritoneal covering into the 

 regular circulatory currents. Further, they may assist to explain 

 the mode of coloration of the tracheae in the experiments of MM. 

 Alessandrini and Bassi, and of M. Blanchard, and also in others, yet 



