Preface. 



Under the above title I purpose, if I can obtain the necessary assistance, to make 

 known little by little the most important discoveries which I have had opportunity to make 

 during my deep-sea investigations in recent years; and I shall consider it my duty first to 

 treat those animal forms which my Father has already partially examined and designated. 

 The present university-program comprises some of these belonging to 6 diiferent classes of 

 animals, namely 2 Polyzoa, 2 Conchifera, 3 Cephalophores, 2 Annelids, 2 Corals and 3 Sponges. 



These animal forms had already been partially destined by my Father for more detailed 

 notice in a university-progi-am similar to that composed on the subject of the Rhizocrinus; 

 and application for the requisite assistance was already sent in to the academical college, 

 when his unexpected death put a sudden end to the important investigations which he had 

 commenced. 



It is therefore with deep gratitude that I here acknowledge the kindness of the col- 

 lege, in confiding to me the elaboration and publishing of the intended program; and although 

 I am well aware of my want of that thorough acquaintance with the invertebrate animals, and 

 of that clear and precise method of treatment which always distinguished my Father's works, 

 it is still a pleasure for me to have opjiortunity given for prosecuting to the best of my power 

 those investigations, to which my Father devoted himself with so much zeal and perseverance, 

 until the day of his death. 



Although, as above stated, the present program was intended to be published by my 

 Father, still the necessary detailed investigations were scarcely more than commenced, for 

 which reason also no manuscript had been compiled. I find however, among my late Father's 

 papers, notes on most of the animal forms mentioned in the following lines, and with respect 

 to some of them also more complete descriptions, which have been of great help to me in 

 the elaboration of the present program. I have also always quoted as conscienciously as 

 possible my Fathers's more coherent remarks, which certainly will have their important value. 

 Where this has taken place, I have always expressly remarked it in the text. Finally I am 

 bound to express my warmest thanks for the valuable information relative to the Mollusca, 

 which has been communicated to me by the celebrated English Conchologist I. Gwyn Jeifreys 

 Esq.; and for the remarkable kindness with which the equally highly celebrated Swedish 



