PORIFERA. II. 



Dendoryx olim) corresponds to the Eciyomn-genus formerly known by the name of Myxilla, Iophon to 

 Pocillon, Iotrochota to Hymetrochota , Grayella (= Yvesia Tops.) to Pytheas, and Tedania to Acheli- 

 derma; also these facts seem to tell against the naturalness of the system. It; is therefore rather prob- 

 able that the division into Mycalince and Ectyonince will have to be abandoned or altered, as has 

 already been advanced by Ridley and Dendy (Challeng. Report, Monaxonidse, 129), at the same time 

 as they reduce Carter's family Ectyonid® to a subfamily, and as will also be mentioned in several places 

 of the present work. I have, however, not yet ventured to abandon this division, as my investigations 

 have not hitherto shown me a more natural way of grouping. For the present the efforts must be 

 directed towards a thorough examination of genera and species, as this will to a high degree facilitate 

 the natural grouping with regard to the higher divisions. 



In the introduction to the first part I have spoken of several descriptive terms and their use, 

 to which I mav here refer. The terminology of the spicules is the same with regard to megasclera 

 and to the forms of microsclera occurring in Heterorrhaphidcc. In the family Dcsmacidonidce, however, 

 we meet new forms of microsclera belonging to the socalled chelate type, and it will be necessary to 

 premise some remarks on the two principal forms of this type 



Chelae and Ancorae. 



The spicules belonging to these forms are at this moment by all authors with the exception 

 of Levinsen comprised under the name of chelae. This name was proposed in 1887 by Ridley and 

 Dendy in Challeng. Rep., and this proposal was of some importance, as up to that time there had 

 been no established term, but terms as anchorates», < Haken , Anker a. s. o. had been used by the 

 different authors. While Schmidt and Carter upon the whole have given good figures of these 

 bodies, Bowerbank on the other hand was highly misled with regard to their forms; even Carter 

 has in 1871 (Ann. Mag. Nat Hist. 4 th ser. VII, 277) pointed out this fact, but Levinsen and after him 

 Ridley and Dendy have rendered a more particular account of it. Levinsen especially Was he, 

 who first and clearly showed (Dijmphna-Togtets zool.-bot. Udbytte, 1887, 354) that Bowerbank gener- 

 ally figures the chelae in two positions, from before and from the side, and interprets these figures as 

 two different forms. Another common mistake, that the tooth of the chela has not been seen, may be 

 found in many works down to the present time; when this is the case the chela is figured with a plate 

 in each end, but without a tooth; or only the tuberculum has been seen and interpreted as forming 

 a small short tooth. This mistake is easily accounted for, as the tooth is often so thin, that it can 

 only be seen under high magnifying powers and by proper light. In this respect Ridley and 

 Dendy 's Monaxonidse (Challeng. Rep.) occupies a high position by its excellent figures of the chelae. 

 Otherwise the mistake is a common one; thus in the works by Vosmaer on the sponges of the 

 Willem Barent -Expedition it is found throughout, and this holds also quite good of his work on 

 the sponges in Bronn's Klassen und Ordnungen, where almost all the figures of chelae are erroneous, 

 no corresponding forms being found in nature. In a paper by Vosmaer and Pekelharing from 

 1898 (Verhaudl. der Kon. Akad. van Wetensch. to Amsterdam, 2, IV, no. 3, 32) entitled On Auisochelae 



