198 



ingestive cells, and the cavity thus arising, i. e. the coelom, is the 

 seat of the monocytic digestive processes. 



Thus, just as in monoblastic forms, the single ingestive cells 

 wandering inwards represent the first stage in the evolution of an 

 internal enteric cavity, so in diploblastic forms such as Porifera the 

 ingestive cells wandering into the mesogloea represent the first stage 

 in the evolution of mesoblastic coelomic cavities (Fig. 2 a). 



(Fortsetzung folgt.) 



II. Mittheilungen aus Museen, Instituten etc. 



1. The Term »Syzygy« in the Descripiion of Crinoids. 



Letter to the Editor. 



eingeg. 28. März 1896. 



With reference to the note on this subject that you kindly published 

 for me in Zoologischen Anzeiger, 19. Bd. p. 57 — 61. Febr. 3, 1896, 

 I have received many favourable expressions of opinion. It will advance the 

 cause of reform if you will kindly permit me to quote two of the most in- 

 fluential , 



Mr. P. de Lori ol Le Fort, who has written more on both recent and 

 fossil Crinoids than any author now living, says: »J'ai toujours compris 

 comme vous le terme de Syzygie, c'est à dire en l'envisageant comme une 

 mode d'union de deux articles, chacun des deux étant une unite. On 

 ne peut pas dire d'une syzygie qu'elle est un mode d'articulation, une arti- 

 culation indiquant toujours un mouvement possible«. 



Mr. Frank Springer, who after the lamented death of Charles Wachs - 

 muth, remains the leading authority on fossil Crinoids in America, writes: 

 »I have read with much satisfaction your paper on , Syzygy ', and I endorse 

 your proposed reform in every particular. I shall follow your plan in this 

 respect in whatever I may do hereafter«. 



It is not too much to hope that a general agreement may now be arrived 

 at on this point. F, A. Bather. 



British Museum (Nat. Hist.) 26 March, 1896. 



2. New York Academy of Sciences, Biological Section. 



March 9th, 1896. — Mr. F. B. Sumner read a paper on «The Des- 

 cent Tree of the Variations of a Land Snail from the Philippines (f, illustrat- 

 ed by a lantern slide. Mr. Sumner described the range in variation in 

 size and markings in the shell, and arranged the varieties in the form of a 

 tree of three branches diverging from the most generalized type. It was 

 shown that these several varieties occupy the same geographical region and 

 Mr. Sumner was of the opinion that their occurrence could not be ex- 

 plained by natural selection since if the colorations were supposed to be 

 protective it would be impossible to explain the evolution of these three ty- 

 pes. Prof. Osborn, in discussion, was inclined to take the same view. 

 Dr. Dyar however, thought the explanation by natural selection not necces- 

 sarily excluded, since the variations seemed analogoiis to the dimorphism in 

 Sphinx larvae, which has been shown by Poult on to be probably due to 

 this factor. — The other paper was by Dr. Arnold Graf on »The Problem of 

 the Transmission of Acquired Characters«. — Dr. Graf discussed the views 

 of the modern schools of evolutionists and adopted the view that the trans- 



