THE APPENDAGES, ANATOMY, AND RELATIONS OF TRILOBITES. 



Fig. 9. A restored composite of Isotelus maximus and /. latus. 

 The exopodites are left out because entirely unknown. Drawn by 

 Doctor Elvira Wood. Natural size. 



I was at once attracted by a specimen of Asaphus, from the Black Trenton Limestone (Lower Silurian), 

 which has been much eroded on its upper surface, leaving the hypostoma and what appear to be the appendages 

 belonging to the first, second, and third somites, exposed to view, united along the median line by a longitudinal 

 ridge. The pseudo-appendages, however, have no evidence of any articulations. But what appears to me 

 to be of the highest importance, as a piece of additional information afforded by the Museum specimen, is 

 the discovery of what I believe to be the jointed palpus of one of the maxillae, which has left its impression 

 upon the side of the hypostoma just, in fact, in that position which it must have occupied in life, judging 

 by other Crustaceans which are furnished with an hypostoma, as Apus, Serolis, etc. 



The palpus is 9 lines in length, the basal joint measures 3 lines, and is 2 lines broad, and somewhat 

 triangular in form. 



There appear to be about 7 articulations in the palpus itself, above the basal joint, marked by swellings 

 upon its tubular stem, which is I line in diameter. 



