CRYPTOLITHUS. 63 



in one or two specimens fragments of forward -pointing endopoclites were seen near the front 

 of the cephalon, and because in other trilobites the second pair of appendages is always 

 directed forward. The remaining three pairs have a more solid basis in observed fact, for 

 the two or three specimens retaining fragmentary remains of them indicate that they turn 

 backward like those on the thorax, and that the individual segments are longer and more 



Fig. 20. Cryptolithus tessellatus Green. A restoration of the appendages drawn by Doctor 

 Elvira Wood from the original specimens and from the photographs made by Professor 

 Beecher. X 9- 



nearly parallel-sided than those of the more posterior appendages. The gnathites of all 

 the cephalic appendages are admittedly purely hypothetical. None of the specimens shows 

 them. As drawn, they are singularly inefficient as jaws, but if, as is suggested by the casts 

 of the intestines of trinucleids found in Bohemia, these trilobites were mud-feeders, ineffi- 

 cient mouth-parts would be quite in order. 



The appendages of the thorax and pygidium can fortunately be taken quite directly 

 from the photographs of the dorsal and ventral sides of well preserved specimens. There 



