358 



ARTHROPODA. 



Fig. 214. Buecal organs of 

 Asaphus platycephalus (after 

 Woodward), h, Hypostome ; p, 

 Palpus ; m, MaxiUa (?) . 



the description by Dr Henry Woodward of a specimen of 

 Asaphus platycephalus, in which, in addition to the lip-plate, 

 there is a jointed filament (fig. 214, 

 p), apparently springing from a max- 

 illa, and being the remains of a max- 

 illary " palpus." 



Still more recently, a specimen of 

 the large Trilobite, Asaphus platy- 

 cephalus (fig. 215), was described 

 by Mr Billings as possessing organs 

 which this distinguished palaeontol- 

 ogist regards as being the remains 

 of legs. The structures in question 

 are in the form of eight pairs of 



apparently jointed appendages, which correspond with the 

 eight segments of the thorax, arising near the middle line, 



and curving forwards. Dr 

 Henry Woodward corro- 

 borates the view pro- 

 pounded by Mr Billings, 

 that these structures are 

 of the nature of ambula- 

 tory legs. Professors Dana 

 and Verrill, on the other 

 hand, regard these re- 

 mains as being " the 

 semi - calcified arches in 

 the membrane of the 

 ventral surface, to which 

 the foliaceous appendages 

 or legs were attached." 



The last additions to 

 our acquaintance with 

 this difficult subject have 

 been made by Mr C. D. 

 Walcott, whose researches 

 have been carried on by 

 transverse and longitudinal 



Pig. 215. AsapJms plutycephalus. Lower Silurian. 



the method of making thin 



sections of rolled-up specimens. This observer has shown 



