196 BULLETD^' OF THE 



and Latreille. The facts brought together by Mr. Billings added to 

 the homology with Limulus, and this was strengthened by the 

 observations of Packard in his discussion of the classification of the 

 JBrayichiopoda, and, later, by the writer in discovering the structure 

 of the cephalic appendages. 



The instances of the discovery of parts of the animal other than 

 the dorsal shell andhypostoma are rare. M. Barrande, in reviewing the 

 reported discoveries made of the appendages of the Trilobite to the date 

 of the publication of his Volume I., 1852, says : " Unhappily all these re- 

 searches have resvdted in nothing more than the discovery of the pieces 

 of the mouth named Hypostoma and Epistoma, and the intestinal 

 canal." Again, in his Supplement to Volume I., 1872, he says : '' The 

 few scattered observations of parts found which might belong to 

 the Trilobites have little value and were accepted as such by natu- 

 ralists." 



" Though disposed to regard these processes figured by Mr. Billings 

 as feet, still the proof is unsatisfactory." * 



" Xo traces of ambulatory or natatory limbs of branchiae or antennae 



have ever been discovered Quite recently, however, a specimen 



of a Trilobite has been discovered in which it is said that the bases of 

 the legs were distinctly recognizable." f 



" No remains of legs are found with any Trilobites, which would 

 not be the case if they had stout legs common to crustaceans of the 

 same size." X 



" Up to this time, no certain indications of the existence of append- 

 ages, nor even of any hard sternal body-wall, have been discovered, 

 though a shield-shaped labrum, which lies in front of the mouth, has 

 been preserved in some specimens." § 



The following appear to be the only instances of the actual discov- 

 ery of some portions of the appendages and structure beneath the 

 dorsal shell. 



1828. M. Goldfuss. As shown in the illustrations, the sections of 

 Phacops figured on Plate II. {Annales des Sci. Nat., Tome XV.) appear 

 to indicate some remains of appendages. M. Barrande, however, thinks 

 that M. Goldfuss failed to prove that the parts he considered as 

 branchial feet were anything more than the result of a defect in the 

 homogeneousness of the rock, or a section of some fragments gathered 



* Development o{ Limulus polyphemus. Packard, 1872. 

 t Manual of Zoology. Nicholson, 1876. 

 t Manual of Geology. Dana, 2(1 od., 1876. 

 § Anat. Invprt. Animals. HiixU-y, 1877. 



