1876.] 17 ; [Minot. 



lutely essential, and that these structures must be arranged in bag- 

 like form, with one opening at least for the ejection, and a multitude 

 of smaller orifices or lateral pores for the introduction of water and 

 food. 



Mr. Hyatt did not desire by the above remarks to convey the im- 

 pression that he was opposed to the Gastrean theory of Haeckel. On 

 the contrary, he thought that that hypothesis has already led to the 

 most important results for Zoology ; and though it was not, and 

 probably could not be, settled for years, it had turned the attention 

 of naturalists to the importance of the comparative study of the 

 early stages of the egg and showed that they had a distinct meaning. 



Whether this meaning had wholly, or only in part, been mistrans- 

 lated by Haeckel, is a question which cannot be answered satisfacto- 

 rily at present. That the gastrula is formed at an early stage of 

 development in nearly all animals except the Protozoa, is not denied 

 by any one, and the enunciation of this fact, though it be attended 

 by many exceptions, had been of invaluable service. Mr. Hyatt was 

 disposed, therefore, to investigate the exceptions which have been 

 found, such as those above described, with the " a priori " view of 

 finding some explanation of the absence in them of a gastrula stage, 

 rather than to use them at present as undeniable evidence of the 

 inapplicability of the Gastrean theory. 



Mr. J. A. Allen gave a resume of a paper about to be pub- 

 lished by him, on North American Beavers, recent and fossil, 

 exhibiting a series of skulls in illustration. 



General Meeting, November 15, 1876. 



The President, Mr. T. T. Bouve, in the chair. Thirty-one 

 persons present. 



The following paper was read : — 



On the Classification of some of the Lower Worms. 

 By Charles- Sedgwick Minot. 



The rearrangement of the animal kingdom, necessitated by the 

 general acceptance of the theory of evolution, assumes the form of a 

 branching system. The worms have for some time been supposed to 



PROCEEDINGS B. S< N. H. — VOL. XIX. 2 MARCH, 1877. 



