136 



Report on Zoology. 



The muscular system must have been highly organized 

 as in Limulus, as, like the latter they probably lived by bur- 

 rowing in the mud and sand, using the shovel-like expanse 

 of the cephalic shield in digging in the shallow paleo- 

 zoic waters after worms and stationary soft bodied inver- 

 tebrates. 



The generative organs were probably very similar to 

 those of the limulus, and the eggs were probably laid in 

 ,the sand or mud, and impregnated hy the sperm cells 

 floating in the water. 



Prof. Gill, of Washington, presented to the Association 

 a communication on " the relations of the orders of the 

 Mammalia." We have but space to notice the five proposi- 

 tions laid down by him as the guiding principles in his 

 studies : 



1st. Morphology is the only safe guide to the natural classi- 

 fication of organized beings ; physiological adaptation the 

 most unsafe. 



2d. The affinities of such organisms are only determinable 

 by the sum of their agreements in morphological charac- 

 teristics, and not by the modification of any single organ. 



3d. The animals and plants of the present epoch were 

 the derivatives, with modification of antecedent forms to 

 an unlimited extent. 



4th. An arrangement of organized beings in a single series 

 is therefore impossible, and the system of sequences adopted 

 by genealogists may be applied to the sequence of the 

 groups of natural objects. 



5th. In the appreciations of the value of groups, the 

 founder of modern taxonomy (Linnaeus) must be followed, 

 subject to such deviations as our increased knowledge of 

 structure necessitates.. 



At the same meeting, a paper by Prof. E. S. Morse 

 attracted much attention. 



