The results recorded in the present paper are the by-product of studies begun by the senior author in 1899, and since 1908 shared by both authors on even terms. At first our interest in the order was almost entirely faunistic and systematic, but as these studies were pushed further it became more and more evident that a much more detailed and minute examination of trepostome structure was necessary to the proper elucidation of generic and family relationships. It was necessary, however, first of all, to bring to a conclusive issue the vexed question of the systematic position of the group, and failing this from the direction of morphology alone, the problem was finally successfully attacked from the standpoint of colonial development (astogeny). The senior author’s paper on the development of the Trepostomata (8)2, published in 1912, leaves no doubt of the Bryozoan affinities of the order.
The results . . .