242 Miscellaneous. 



division of the organs, but rather a production of new organs super- 

 added to the primary organ, or what comes to the same thing, a re- 

 petition of the same organ on a part of the body where it should exist 

 alone*. — Revue et Magasin de Zoologie, Sept.* 1851, p. 453. 



Description of a new species o/" Macgillivrayia. By A. Adams, F.L.S. 

 To the Editors of the Annals of Natural History. 



R.N. Hospital, Ilaslar, Gosport, Feb. 23, 1852. 

 Gentlemen, — I send you the description of a new species of 

 Macgillivrayia, a genus of mollusca just established by Prof. Forbes, 

 and as it is a member of a very novel form, I shall feel obliged by 

 your inserting it in your next number. 



I remain, Gentlemen, yours very truly, 



Arthur Adams, F.L.S. 



Macgillivrayia spinigera, A. Adams. 

 Testa turbinata, tenui, cornea, glabrata, semipellucida, imperforata ; 



spira brevi, anfractibus subplanulatis ; apertura oblonga, Integra, 



antice subangulata ; labio recto, antice producto, in spina acuminata 



desinente. 

 Hab. Mindoro Sea. 



The great peculiarity of this species is the circumstance of the 

 columellar lip ending anteriorly in a produced spine ; the surface 

 moreover is glossy, the shell more transparent, the whorls of the spire 

 less rounded, and the spire itself less prominent than in M. pelagica 

 of Forbes. The operculum is that of the genus. 



On the Anatomy and' Physiology o/Salpa and Pyrosoma. 

 By Thomas H. Huxley, F.R.S. 



The object of the author in the present paper is to inquire into 

 the true nature of the singular phenomena of reproduction in the 

 Salpaz, whose existence was first demonstrated by Chamisso twenty 

 years ago, and which have formed the basis of the theory of " alter- 

 nate generations." 



The author refers to M. Krohn as the only writer who has pre- 

 viously entered thoroughly into this subject; but while he bears 

 testimony to the extreme accuracy of M. Krohn's statements, he sub- 

 mits that, as the latter are published in a very condensed form only, 

 and without figures, they cannot affect any value that may attach 

 to his own independent researches. 



The forms of Salpa examined were the S. democratica and S. 

 mucronata. 



The author first describes their outward form, and shows that 

 they are so different in appearance and in some points of organiza- 

 tion, as to fully warrant the assumption (if they belonged to any 

 other family) that they are different species. He then proceeds to 

 describe the various organs in detail ; first, however, discussing the 



* In a subsequent number of the ' Revue et Mag. de Zoologie,' M. Gue- 

 rin Meneville states that a similar deformity in the right antenna of a male 

 cockchafer had been described and figured by M. Wesmael in the ' Bul- 

 letins de l'Acad. des Sciences de Bruxelles' for 1849. 



