EXPLANATIONS OF PLATES. 
NOl'E. — Unless otherwise stated, the figures are of the natural 
size, and all measurements in the text are given in 
decimal fractions of the metre. 
PLATE I. 
Page. 
Fig. 1. Gostfordia truncala, gen. ct. ,sp. nov. ; head and abdominal region, one half nat. size. 
orb., orbit; x., [)osterior margin of operculum or pectoral arch ... ... 5 
Ditto : caudal region. J>h\, pelvic tin. 
