294 THE CANADIAN NATURALIST. [Jan. 



of our known fossil insects are from the Devonian strata of New 

 Brunswick ; while in Tertiary rocks their remains have been 

 found in only one locality, near Green River, Colorado. No 

 fossil spiders have been discovered in North America. 



On the Winooski Marble of Colchester, Vt.; by 

 Prof. C. H. Hitchcock. — This beautiful marble, which is found 

 in Potsdam rocks, near Burlington, consists of a silicious dolom- 

 ite, containing imbedded nodules of silica, enclosed in calcite. 

 The prevailing color is red, mottled, and veined with white, 

 brown, chocolate, yellowish, and whitish tints. So highly is it 

 valued abroad, that considerable quantities are exported to Italy 

 for the use of the sculptors of that country. The presence of 

 the quartz, however, renders it somewhat difficult to work. 



On the Zoological Affinities of the Tabulate Corals ; 

 by Prof. A. E. Verrill. — The questions discussed in this paper 

 were the position of the tabulate corals among Polyps, and the 

 true value of the tabulate structure in classification. Coral-like 

 forms are produced by Protozoa (Eozoon, Polytrema, Sponges, 

 etc.), Molluscan corals (Bryozoa), Hydroid corals (Sertu- 

 laria, etc.), Polyp corals (Gorgonia, Tubipora, Madrepora, 

 etc.), and by vegetable corals (Nullipora, Corallina). Most of 

 these have been carefully studied. Two important groups, 

 however, are still involved in considerable doubt,— the Cyatho- 

 phylloid corals (Rugosa, Edw.), and the Tabulate corals. 

 The former are entirely extinct, and their structure may long 

 remain somewhat uncertain The latter are represented in 

 tropical seas by several genera and numerous species. Usually 

 they have been considered true Polyps ; but some zoologists urge 

 their affinity with the Bryozoan mollusks, while Agassiz, after 

 examining the genus Millepora, places the whole group among 

 Hydroids. Prof. Verrill considered the point as only settled so 

 far as Millepora and its allies were concerned, and requested Mr. 

 F. H. Bradley, while collecting, at Panama, for the Yale College 

 Museum to study the structure and habits of a species of 

 Pocilopora found at the place. The descriptions and figures of 

 the animal show it to be a true Polyp, scarcely differing from 

 Porites, except in the position of the tentacles. The animals are 

 exsert when expanded, and have twelve equal cylindrical tentacles 

 surrounding the margin, in a single circle, six of them being held 

 horizontally, and the alternate ones erect. Prof. Verrill, there- 

 fore, concludes that the tabulate structure is of secondary 



