which assistance I here express my thanks; especially such comparison is necessary, with a view 

 on the numerous species of the brothers H. and A. Adams, as their descriptions are often very 

 short and insufficiënt and have mostly not been accompanied by figures. I have to thank also 

 many other persons, who assisted me by loaning books or specimens or by giving advice. 



The conservation of the specimens was as a rule very good, hovvever I think formol 

 must be rejected if one cares to keep the shells in good condition; it seems that it renders the 

 shells very brittle and their surfaces dull. 



Those specimens to which an asterisk has been prefixed, have not been taken by the 

 Expedition, but they belong to the collections of the Zoological Museum of the University or 

 of the Royal Zoological Society of Amsterdam. 



At the end of this part is annexed an appendix by Prof. R. Bergh, who had received 

 amongst the Nudibranchs a few Prosobranchs, and has described them or has given anatomical 

 particulars; a few of these species belong to the Taenioglossa, which will form the second part 

 of the Prosobranchs. 



