MUSEUM OF COMPARATIVE ZOOLOGY. 197 
by accident in the vacant carapace of the Trilobite before its petri- 
faction. 
1846. Prof. Beyrich presented the account of the discovery of the 
intestinal canal of Zrinucleus. This was fully corroborated by M. 
‘Barrande, and more recently by Dr. Volborth. 
1863. Dr. Volborth discovered the intestinal canal of an Z//enus. 
It was constricted, so as to appear to be an articulated organ. 
1870. Mr. E. Billings. This discovery is mentioned on a pre- 
ceding page. 
. Mr. Henry Woodward mentions the discovery of the jointed 
palpus and one of the maxillæ of an Asaphus, in position by the side 
of the hypostoma. 
1876. Mr. C. D. Walcott announced the discovery of the natatory 
and branchial appendages of the Trilobites. 
1877. Mr. C. D. Walcott. Additional evidence is given to show 
the presence of manducatory jaws, ambulatory legs, and branchiæ, in 
the genera Calymene and Ceraurus. 
The discovery by M. Eichwald of an isolated crustacean (?) leg, il- 
lustrated on Plate VI. fig. 4 of this paper, is an instance of discoveries 
mentioned by M. Barrande as having little value. Mr. Billings first 
discovered evidence of the presence of ambulatory legs in the Trilobite, 
and this was so far from satisfactory that Messrs. Dana, Verrill, and 
Smith pronounced the so-called legs not to be such,* and the discovery 
has been entirely ignored by many recent authors in zoólogy, as not 
having any bearing on the question of the zoólogical position of the 
Trilobite. Others, however, have accepted it, as has been mentioned. 
The discoveries of the writer have been received in about the same 
manner. So many times the discovery of the feet and other organs 
of the Trilobite had been announced, and subsequently proved to have 
been based on insufficient evidence, or no evidence at all, that natu- 
ralists were disinclined to accept any statement that such discoveries 
had been made, without absolute proof of their genuineness. 
From the illustration given by Mr. Billings of the Canadian speci- 
men of Asaphus, and an examination of a cast of the original, I cannot 
but think that the remains are what he considered them to be. Al- 
though the specimen does not reveal the structure of the Trilobite as 
we now know it, it is the first that gave any positive information of the 
presence of jointed legs beneath the thorax of the Trilobite. 
* Amer. Journ, Scien. and Arts, 3d series, I. 320, 1871. 
