nadiata. 0945 



frequent yet abnonual aberration from the typical characteristics of the species, not 

 confined to any peculiar soil or locality; example, Miana strigilis, Lin., var. ^thiops, 

 Hmv. Permanent variety or race, a variety confined to pariioiilar localities, and here- 

 ditary in all its distinguishing!; peculiarities; example, Noctua conflua, 7>., and 

 Lycaena Ariaxerxes, Fah., wliich by many entomologists (of whom I am not one) are 

 considered more northern varieties of N. festiva, W.V., L. Agestis, W. V. Lusus or 

 sport, an nnusual and extraordinary divergence in colour and markings from the 

 typical characteristics of the species ; example, a black specimen of Chelonia CHJa or 

 C. villica, Linn. I am almost ashamed to offer these defective and inaccurate defini- 

 tions to your readers ; but, as I said before, I hope no one will hesitate to set me right 

 wlietever he thinks I am wrong. One word in conclusion, respecting the term "race" 

 or "permanent variety," which has lately become so common. The opinion which I 

 expressed (Zool. 6247) has in no way altered. As far as Lej)idoptera are concerned 

 I do not believe in the existence of these " permanent varieties." I have never heard, 

 read or seen anything which convinced me; and I think the conclusion rests upon 

 most insufficient evidence. We heard a great deal, some two years since, about T. 

 crepnscularia, W. V. (laricaria, Douh. Cat. 1st ed.) being a race of T. biundularia, Esp. 

 (crepuscularia, Doub. Cat. 1st ed.), and M. rivata. Hub., a mere permanent variety of 

 M. sublristata, Haiv. (alchemillaria, Doub. Cat. 1st. ed.) ; but the whole four species 

 have been carefully bred from the egg during the past season, and proved to be indu- 

 bitably distinct ; and I believe that the further and closer experiments are carried the 

 more plainly will the theory be shown to be fallacious. — Id. 



On the Transverse Fission of Aiptasia Couchii. — Mr. F. N. Broderick's commu- 

 nication to Mr. Gosse on the transverse fission of Aiptasia Couchii (Zool. 6911) is of 

 very great interest, and, I believe, the first recorded notice of that mode of increase in 

 the Actiniadae. In his ' Actinologia Britannica' Mr. Gosse has properly placed this 

 animal between Sagartia and Anihea, genera in which fissiparous reproduction is fre- 

 quent, although after different fashions. In Anthea the fission is vertical, separating 

 the polype into two distinct halves, each possessing its share of fully-developed inter- 

 nal and external organs; fissiparous increase in Sagartia, on the contrary, consists of 

 the detachment of little ragged bits, only from the base of the animal, and may be 

 considered as an irregular mode of budding, since the separated parts at first contain 

 no specialised structure, but only the vital power requisite for its development. The 

 division in Aiptasia partakes of the character of both these forms of increase, like that 

 in Sagartia from taking place only at the base, and Anthea-like in being a complete 

 section of the body, although a transverse oue ; each portion also being to a certain 

 extent complete in itself. With regard to the mode of increase of Aiptasia in the 

 Zoological Society's collection, I think Mr. Broderick must have been misinformed, 

 perhaps by some one who was locum tenens for the regular attendant during the 

 important hour of dinner. There are now three specimens of this polype in one of the 

 centre tanks, the two smaller examples being the produce of the other, and, as Ten- 

 nent, the keeper, has often told me, the result of transverse fission. The first young 

 one was so small and well-proportioned that I could hardly believe it had been pro- 

 I duced in any other than the usual manner ; but the second had a very different shape. 

 It appeared last August, and when three days old the body was very short and thick, 

 XVIII. X 



