Porifera. 



I. 



By 



William Lundbeck. 



The present treatise is the first part of a work on the Porifera collected b\- the Ingolf-expedition. 

 The material for this work, however, does not consist of that of the Ingolf-expedition only, bnt 

 I have, for the sake of completeness, inclnded all the sea-sponges, fonnd in our Museum, from Green- 

 land, Iceland and the Faroe Islands, and upon the whole from the territory treated of here. The latter 

 material has especially been collected by the Greenland-expeditions that have been sent by the Com- 

 mission for the geological and geographical examination of Greenland; partly also by the men of war 

 that have navigated the seas round Greenland and Iceland, as also by some other collectors; especially 

 must be mentioned a considerable collection, made by Dr. Morten sen in 1899 at the Faroe Islands. 

 Of the whole material, howe\-er, the portion collected by the Ingolf-expedition during its two cruises in 

 1895 and 1896 forms by far the greater part. The collection of sponges made by this expedition was 

 quite exceptionalh- great, greater, I think, than an\- made by any single expedition before. Finally I got 

 from the museum in Bergen by the kindness of Dr. Brunch horst the sponges of the Norwegian 

 North-Atlantic Expedition, which I have included here, as the earlier work on those sponges needed 

 a revision. The geographical territory of the present work may therefore be given thus: the eastern 

 part of the Davis Strait and the sea north of a line through the southernmost station of the Ingolf 

 at about 57" L. N. across to the south of the Faroe Islands, that is to sa>-, the whole of the North- 

 Atlantic (species from the Norwegian fjords, however, have not been included). From this territory I 

 have endeavoured to include all the species, also those that are not found in the material, but have 

 been mentioned in the literature as found within the territor\'. 



With regard to the terms used in the descriptions I shall premise a few remarks. The 

 terminology employed in describing the spicules is mainly the same as has been used by Ridley 

 and Dendy and by Topsent, and upon the whole by all recent authors, .so that an explanation will 

 be unnecessary. 



For the more or less membranous part of the body of the sponge which forms the surface 

 and covers the subdermal cavities, the term dermal membrane has been employed. It may be 

 thinner or thicker, and more or less pronounced; where the subdermal cavities are large and widely 



The Ingolf-Expedition. \ I. i. I 



