$ PREFACE 
certainty with me, that the more teachers put themselves 
in direct communication with original observers, the more 
they will learn, and the better fitted they will be to teach. 
I have long been interested in sponges, and began 
to pay attention to them in 1870, when on a visit to Key 
West, and have studied them constantly ever since, when- 
ever opportunity offered, both in Florida and in the Baha- 
mas, and other West Indian Islands, | 
The results of these studies are being published in my 
Contributions to Science, beginning with Vol. II, and con- 
tinued through other volumes, but I have here given much 
of this matterin a condensed form. 
Other numbers of this series containing accounts of 
the Corals, and Gorgonias, Echinoderms and Starfishes, 
Mollusks, Insects and Vertebrates will pOHOW as rapidly as 
it is possible to publish them. 
i¥ if M. 
West Newron, Mass, 
January, 1898, 
