348 Miscellaneous. 



through the iiiterraaxillaries to the true maxillary bones in the 

 rodents generally. But to return to Talpa leucura : following the 

 minute lower canine and the canine-like first lower prsemolar of this 

 species, there are two small ])raemolars anterior to the carnassier or 

 last of the series, and the first of these is conspicuously much smaller 

 than the second ; in T. microura the two are of equal or nearly 

 equal size, and occupy more space longitudinally ; while in T. europcea 

 these and the carnassier successively enlarge in a regular gradation, 

 the latter being proportionally smaller than in the two Indian species. 

 Both scissor-teeth are indeed most developed in T. microura, and the 

 teeth generally are more robust. 



The specimens of T. microura from Asam, like those of Nepal, 

 have generally a very minute tail, which can at least be distinctly 

 enough felt under the fur ; but those from the vicinity of Darjiling 

 have no external trace of tail, whether sent as skins or in spirit. I 

 have found, however, no perceptible difference in the skulls and 

 dentition, nor in any other character whatever, that should warrant 

 us in considering the tail-less Darjiling Moles as a distinct species, 

 separable from T. microura. The Society's Museum contains T. 

 leucura stuffed and in spirit, and the skull of the specimen preserved 

 in spirit has been extracted and cleaned ; while the dentition of the 

 stuffed specimen is exposed, and is quite similar to that of the other 

 here described. It is not improbable that T. leucura may extend 

 its range eastward into China ; and in that direction we may look for 

 additional species of Talpa, if not also in western Asia. In Africa 

 the genus is unknown, but is represented in the south by Chrysochlore ; 

 in North America by Scalops and Condylura ; while in South America 

 the Insectivora, Cuv., do not occur, their functions being performed 

 by numerous diminutive species of Didelphys, as also may be said 

 in Australia by the Perameles tribe ; and it is far from unlikely that 

 Australia may yet be found to produce a fossorial marsupial form, re- 

 sembling the Moles as other Marsupialia present an analogical but 

 superficial hkeness to certain other Insectivora. — From the Journal 

 of the Asiatic Society of Bengal, No. III., 1850. 



On the Analogy between the mode of Reproduction in Plants and 

 the "Alternation of Generations " observed iti some Radiata. By 

 James D. Dana. 



The very remarkable fact that a Polyp and a Medusa may be in 

 some instances different states of one and the same species, has been 

 well established of late by the researches of Sars, Dalyell, Steenstrup 

 and others ; and recent important observations have been made on 

 the subject by Professor Agassiz. The alternations are as follows : — 



1 . The Medusa produces eggs ; — 



2. The eggs, after passing through an infusorial state, fix them- 

 selves and become polyps, like Corynee, Tubularity, or Campanu- 

 larice ; — 



3. The polyps produce a kind of bud that finally drops off and 

 becomes a Medusa. 



