PREFACE. XV 



greatest affinity with Mordellona p. 501 (Rhipiphorus and Symbius, 

 p. 502), to which indeed BURMEISTER (Handbuch der Naturgesch., 

 1837, p. 343) had already referred them, and afterwards also 

 SHUCKARD, and more recently NEWMAN Zoologist, 1850, pp. 2684 

 2694. 



The multiplication of insects without previous copulation was 

 noticed in Aphis at pp. 263, 264. It has been observed in other in- 

 stances, as in Lepidoptera and in Bees, but under different circum- 

 stances. In Aphis the parent is imperfectly developed, there is neither 

 bursa copulatrix nor receptaculum seminis. In the others both these 

 organs are complete. The eggs laid by the virgin queen-bee always 

 produce males: those which are impregnated produce females (work- 

 ing bees or queens) ; the queen has the power at will of laying an 

 egg that shall produce a male or a female, i.e. she can during ovi- 

 positure impregnate the egg with spermatozoa or not. In Bombyx 

 mori SIEBOLD found that only few of the uniinpregnated eggs are 

 productive, and that from these males or females proceed indis- 

 criminately. In Psyche it was males that required impregnated 

 eggs for their production. 



See OWEN On Parthenogenesis, London, 1849 an( i V. SIEBOLD Wahre 

 Parthenogenesis, Leipzig, 1856. 



In the Crustacea the remarkable discoveries of DARWIN respect- 

 ing the Cirripedia were referred to by the translator at pp. 608, 

 609, and 635640. 



Amongst the Molluscs, with regard to the Lamellibranchiata, 

 if Prof. VAN DER HOEVEN had to write his book again he would 

 entirely alter the order of succession of the families. 



What had become known respecting the Hectocotylus of di- 

 branchiate CepJialopods was recorded by the translator at pp. 

 821823. 



With regard to the second volume of this work the translator 

 has made few additions beyond the notice of the principal fossil 

 reptiles at pp. 321 327. But such large additions and alterations 

 have been contributed by the author himself, particularly in 

 the class of Fishes and that of Reptiles, that this volume may be 

 regarded rather as a third edition of the original, than simply a 

 translation of the second. 



At p. 37, note 1 it is stated that in the class of fishes alone the 

 existence of corpora Wolffiana had not been ascertained. This 



