176 Transactions. — Zoology. 



to avoid it. The field is, however, a splendid training-ground 

 for the earnest student, and there is much work of great value 

 to be done that can well be done by an observer who is con- 

 tent to describe, in words and by drawings, what he sees and 

 no more, and who, when resorting to diagrams, makes it clear 

 that they are diagrams, and not drawings. Some of this work 

 in relation to the New Zealand sponges, it is hoped, may be 

 done and may be described in the series of papers contem- 

 plated, and in the criticisms that will be evoked. Only the 

 publication by each worker of what is known to him, or of 

 what he thinks is known to him, and the correcting of his 

 errors by other workers, can prepare the way for the produc- 

 tion of a monograph of the group in New Zealand. 



The worker that deals with a group of which there is a 

 widely-recognised classification is enabled to reduce his ma- 

 terial to order with some confidence and ease ; but in this 

 group every writer of note, and many a one besides, has pro- 

 posed a scheme that is largely his own, and often he has been 

 the only worker that has adopted his scheme. There has,^ 

 however, been advance ; and the classification of the sponges, 

 which might have been regarded as a very murky and troubled 

 fluid a few years ago, has become clearer and colloid, and 

 may be expected to solidify, in time, in a satisfactory form. 

 The advance that has been made is very largely owing to the 

 magnificent work done by the men to whom the material of 

 the " Challenger" expedition was intrusted, and the classifi- 

 cation proposed by them will be generally followed in these 

 papers. 



I wish to acknowledge the great help and encouragement 

 that I have received from Dr. Dendy, one of the foremost 

 workers of the day. This help was not confined to good 

 advice, but took also the concrete form of a nmiiber of 

 European and Australian types of calcareous sponges, in- 

 cluding a large number of the blocks from which Dr. Dendy 

 had cut his own sections. The confidence so generously 

 bestowed on an unknown worker has formed one of the 

 strongest reasons I have had for persevering in this work. 



As it must be long before the material collected is sufficient 

 for the production of a monograph, and as much preparatory 

 work has to be done, and some of it probably undone and 

 done again, it is proposed," in the interests of students gene- 

 rally, to describe the New Zealand sponges in something like 

 their natural order, beginning with the Calcarea. As, more- 

 over, the literature of the subject is very scattered, and much 

 of it is difficult to obtain, it is deemed advisable to copy the 

 descriptions of New Zealand forms that may be identified as 

 already described, amplifying and illustrating the description 

 where it seems necessary to do so. 



