ERRATA IN PART I. 



It is particularly requested that the following corrections be made with the pen at page v of 

 the Introduction : — Foot-note, four lines from the bottom of the page, after B b, instead of " nasogastric," 

 read "mesobranchial ; " after B c, for " metagastric," read " metabranchial ;" after Ca, for "epigastric," 

 read "epicardiac ; " after C b, for "metagastric," read "metacardiac." 



Page vii, line 6, for " Cyclocoryster," read " Cyclocorystes." 



Page 38, line 3, the quotation from Davila should be transferred to the synonyms. 



Explanation of Plate VI, add — " 1 1. Male abdomen of the same." 



