Institule of France, 1 i9 



which it contains appeared most frequently of a colour similar 

 to that of the greasy matter which always fills a part of the body : 

 it is not very liquid, particularly ia the voracious larvae. The 

 diameter of the vessel is more equal in the larvae, in which th» 

 fat is diffused more equally; and the inequalities of its various 

 parts are proportioned to those of the fat in the corresponding 

 parts o'i bodies. The nerves and tracheae abound more in the dor- 

 sal vessel of the larvae than in that of the perfect insect : its con- 

 tractions are stronger, but less frequent. From these and other 

 facts, the author thinks it may be concluded, that the function 

 of the dorsal vessel is to produce fatty matter; and in order 

 th:?reto, tliat it absorbs a part of the nutritive liquor diffused 

 throai;h the cavity of the body by the sides of the intestines ; 

 and that it makes it afterwards transude through the scales of 

 the adipose substance, where the fat receives its final elabora- 

 tion. 



M. de Serres iias interwoven some valuable observations on 

 the varieties of structure of the tracheae in dilferent families of 

 insects, among wliich we ought particularlv to remark those 

 xvhich concern the mechanism of the vesicular trachea: he con- 

 cludes by a detail of all the anatomical characters of the divisions 

 which he thinks ought to be established among the articulated 

 animals, and particularly insects. We regret that this interest- 

 ing elucidation of comparative anatomy is too long for insertion 

 in tiie i.resent sketch*. 



.M. Aiontegre, a physician at Paris, has made some curious 

 observations on the habitudes of the lumhrici or earth-worms, 

 and some new remarks on their anatomy. These animals are 

 hermaphrodites, each being productive of voung: nevertheless 

 there is no copula, or this seems to take place without any in- 

 tromission of i)arts, and merely by the excitement of the move- 

 ments necessary for fecundation.' This takes place chiefly in 

 June and .July. The worms unite by means of a swelling at the 

 antei ior part of their body, and by wliich they adhere firmly to 

 e.'.ch otiier. The young wonns first show themselves in white 

 organs placed in front, on botli sides of the stomach, and slide 

 between the intestines and external muscles along a reser- 

 voir situated in the thick part of the tail, where they are found 

 full of hfe. The lumhrici exhibited nothing to our observer 

 which could induce him to ascribe to them the faculty of being 

 affected by liglit or sound ; but he was convinced that they did 

 not confine themselves to the earth alone, for he found in ther 

 jnteaiiues the lemains of animals and plants. 



• The whole of M. Semes' valnnble p.iper will be found in the pages of 

 the Fliiiobophical Magazine.- Ej.ir. t' fa "' 



K 3 • XXVI. /«. 



