90 



formed of the thickened outer walls and possesses a cavity within, which again is separated 

 from another cavity by a muscular floor (PI. XYIII, fig. 136/). In the region where the thin 

 walls of the outer wall of the float join the thick walls of the basal part are found "spherical 

 bag-like structures" (PI. XVIII, fig. 1 t,6 £-m). The cavity of one of them was filled with bodies 

 resemblinof those found on the lower floor. 



The e.xternal surface of the thick walls is covered with clusters of bodies resembling 

 sexual clusters in Physalia (PI. XVIII, fig. 136). 



This is a summar\- of what Fewkes could distinguish in his very imperfect material. 

 We will not discuss here the suppositions which Fewkes makes with regard to the position of 

 ■ Angelopsis in the system. 



In i8S8 Haeckel describes in his Challenger Report a new order o^ Siphonophores,\\\\ic\\ 

 he calls Auronectae and which he considers absolutely new to science. They are characterized 

 by the appearance of a new ?nedusotd-\\ke. appendage called by him "■mirophore' . He includes 

 in this group (but doubtfully) F"kvvkes' Angelopsis (88b p. 301), finds some relationship to his 

 new genus Auralia but on the whole finds Fewkes' description of 1881 too inaccurate and the 

 latter's examination of Angelopsis too superficial to allow of his identifying Fewkes' Angelopsis 

 with his Aitralia. 



Fewkes in 1889 (89a) defends himself and gives a more extensive description of his 

 specimen, recapitulating the one which he gave in 1884 and adding a few particulars concerning 

 the bag-like structures, which in opposition to Haeckel he continues to find dissimilar from 

 nectophores. P'irst of all he finds that it is very difficult to detach them from the float and 

 secondly they have no bell-openings nor radial tubes. He thinks it not impossible that they are 

 homologous to the aurophores, but unlike them they have no external openings. Of great interest 

 in this publication is the more extensive sketch given of a section through the float and polyp- 

 stem (89a PI. VII, fig. 2) taken in the transverse direction, in which an opening is found inside 

 the pneumatosaccus, which according to I""e\vkes is an opening of one of those bag-like structures 

 into the float (PI. XVIII, fig. 136 0.). Around this opening is an area having an elongate, elliptical 

 shape, which is visible in the sketch as a lighter spot around the darker opening of which we 

 spoke above. In describing Archangelopsis we shall have occasion to show the great importance 

 this light spot plays in the exact comprehension of the structure of the pneumatophore in this 

 new genus. 



We agree with Chun (97 a) that Fewkes' paper would have become decidedly more 

 valuable, had he made any series of sections through his specimen ; but as he says himself, he 

 did not intend his report to be either anatomical or histological (89a p. 155). 



Comparing our material of the Siboga expedition with Haeckel's extensive publication 

 of 1888 (Challenger Report) it seems to us that we are able to give an entirely new view of 

 the structure called aurophore and in doing so w^e shall have to criticise Haeckel's conclusions 

 in many instances. 



It would seem to us, always judging by the facts, obtained in examining our own material, 

 that Haeckel has often drawn too largely on his imagination. It appears to us he made one 

 fundamental mistake and that, by not carefully comparing his material with the drawings of 



