1 62 NATURAL SCIENCE. Sept., 



as far as possible, to a general scientific assembly, and there is then 

 no fear that this great meeting will lose any of its long-sustained 

 interest and importance in the intellectual life of the nation. 



Trilobites. 



Considering the abundance of the familiar Palaeozoic fossils 

 named Trilobites, it is singular how little is known of their appendages. 

 Twelve years ago the researches of Mr. C. D. Walcott showed that 

 the ventral side of the body was covered with a hardened arch over 

 each segment bearing a pair of limbs, while the head was provided 

 with four pairs of appendages, acting as jaws at the base, as in the 

 modern King Crabs. 



More than 20 years ago, Dr. Henry Woodward also discovered a 

 kind of palpus attached to an inferior head-plate ; but conditions of 

 fossilisation more satisfactory than any of those under which 

 trilobites have hitherto been met with can alone permit much 

 advance is our knowledge of the subject. 



A stratum in the Hudson River shales, near Rome, New York 

 State, it is interesting to note, has yielded materials for the first step 

 in this advance. The discovery of a number of specimens of 



Head of Trilobite showing Antenna. 



Triarthrus becki by Mr. W. S. Valiant, enables Mr. W. D. Matthew 

 to contribute an important paper on the subject to the current issue 

 of the Amcv. Journ. Sci. (ser. 3, vol. xlvi., pp. 121-125, pi. i.) ; and it 

 now appears that not only had the trilobites the appendages already 

 observed, but also a well-developed pair of antennas. We reproduce 

 a figure of the best specimen above. The antennae are composed of 

 a great number of joints, each of which is conical, about half as long 

 as wide, and smallest at the base. They seem to have been of a 

 structure less firm and thick than the substance of the carapace; and 

 just over the spot where they come out, the anterior margin of the 





