Zoological Society. 53 



Gen. 35. Siphonotus, Brandt. — Ocelli 2, in serie simplici 

 transversa. 



Fam. 10. Siphonophoridce, Newp. (Typhlogena, Brandt.) — Oculi 

 nulli. 



Gen. 36. Siphonophora, Brandt.— Caput conicum, elonga- 

 tum. Nutritionis organa rostriformia, elongata. 



The author then proceeds to treat at considerable length of the 

 external anatomy of the Myriapoda, commencing with the composi- 

 tion and mode of development of the segments and their appendages, 

 and comparing them in these particulars with Insects. The variations 

 in the several genera of Myriapoda are particularly noticed ; and the 

 principles on which their development, in its various modifications, 

 depends, are elucidated by numerous observations on their mode of 

 growth. The structure and development of the head are next treated 

 of in detail in the different families and genera of the Chilopoda ; and 

 the organs of nutrition are especially examined with reference to their 

 development and analogies. This branch of the subject is concluded 

 by an appreciation of the relative value of the different parts of the 

 skeleton in furnishing generic and specific characters. 



The systematic description of the families, genera and species of 

 the Myriapoda Chilopoda completes the memoir ; which was accom- 

 panied by a series of drawings, illustrative of their external anatomy 

 and generic characters. 



ZOOLOGICAL SOCIETY. 

 Oct. 24, 1843 — William Yarrell, Esq., Vice-President, in the Chair. 



Mr. Bridges on the habits, &c. of some of the smaller species of 

 Chilian Rodents.. 



" Mus longicaudatus, Bennett. — I found this mouse in the valley 

 of Quillota, fourteen leagues distant from Valparaiso, in the vicinity 

 of brooks and rivulets, amongst weeds and long grass, although from 

 its appearance I should imagine it seldom takes the water. In that 

 part of Chile it is not rare, but it cannot be considered a common 

 species. In the province of Colchagua I have found another species 

 approaching M. longicaudatus and more abundant, differing slightly 

 in the length of its tail, and in being somewhat less in size. At first 

 sight the two species are liable to be confounded. Probably this is 

 the same species mentioned in p. 40 of the ■ Zool. of the Voyage of 

 the Beagle ' by Mr. Darwin as being so numerous in the province of 

 Concepcion. 



"Mus longipilis — Waterh., ' Voy. of theBeagle,' — inhabits the pro- 

 vinces of Aconcagua, Valparaiso and Colchagua. Its favourite haunts 

 are the hedges made of bushes of Mimosa Cavenia and Trevoa tru 

 nervis, also other shrubs used indiscriminately for that purpose. It is 

 necessary to explain that the hedges of the fields of Chile are renewed 

 every year by throwing on each side of them new layers of bushes, 

 and that they are frequently two or three yards across, forming thus 

 a mass of decomposing wood, which gives excellent shelter for the 



