PREFATORY NOTES. 



The North Atlantic is here regarded as limited by lat. 35 N., 

 or as extending a little to the South of the Strait of Gibraltar on the 

 Eastern and to about Cape Hatteras on the Western side. 



All the Sponges of the following lists were found within the 

 area thus embraced, but some of the Foraminifera are from the more 

 tropical parts of the Atlantic, these are indicated by an (*) placed 

 before the number. Most of them may, however, be expected to be 

 found hereafter North of lat. 35 on the Western side of the 

 Atlantic. 



The nomenclature of the Sponges is at present in deplorable 

 confusion. To properly synonymize the species of the following 

 lists would require years to be devoted to their examination and 

 study. Moreover, since the value of the present collection consists 

 in the fact that almost all the representatives in it are types or 

 portions of types, and on this account most important for future 

 reference, I have retained throughout the nomenclature of the 

 respective describers, who have named the species. 



The British Calcarea, collected by myself, were used both by 

 Dr. Bowerbank and by Prof. Haeckel in the preparation of their 

 works ; and the Siliceous Sponges all passed through the hands of the 

 former, and are for the most part mentioned in his monograph, while 

 a large number of them are, at the present time, unique types. The 

 remaining portion of this collection embraces specimens or sections 

 and mountings of the spicula of types for which I am indebted to 

 almost every author who has written on the Sponge-fauna of the 

 Atlantic and Arctic oceans. 



I shall be much obliged to any naturalists who can in the future 

 help to extend the collection in a similar manner, and to whom in 

 return I shall be glad to send specimens or mountings of types. It 

 will be seen that this collection is very rich in Northern Sponges, but 

 there are about one hundred described Mediterranean species absent 

 from it, nor have I those European freshwater forms, which are not 

 found in England. 



