Studìes on Sponges. II — IV. 485 



bessa H. or gìve it a new uame but it is not the old L. aspera. I how- 

 ever consider ali tliese tog-ether as varieties of one species, for which 

 then the name aspera should bave priority. Accordiug to Poléjaeff's 

 new system in which however the old generic names are kept as far as 

 possible, the Sponges under description belong to Leucoma. 



How much the Sponge which Haeckel called L. aspera varies in 

 externa! appearance one may see on bis piate (1. e. III. taf. 35). 

 Ou Piate 28 I bave illustrated several other varieties. Partly one would 

 cali them L. aspera^ partly cramhessa. partly perhaps give tbem new 

 names. Of ali these as well as of typical specimens oi aspera and cram- 

 hessa the anatomy does not show Constant differences 

 valuable enough to account for species. 



As for the external appearance I bave observed that there are ali 

 desirable transitions between the ratber compressed thin walled var. 

 cramhessa and the more or less round var. typica. The diagrams of 

 macroscopical sections on Piate 28 may clear this up. It is evident that 

 the flattness of the former is not Constant as Haeckel says (1. e. II. 

 p. lS3;i. The gigantic rods are not always so frequent as is figured on 

 Haeckel's Plates. As a rule we find them stronger. more frequent and 

 farther protruding in the var. typica^ a little tbinuer, rarer and less pro- 

 truding in the var. cramhessa. As a rule the walls of the former are 

 also tbicker but the correlation is not always so strongly marked out. 

 Fig. 3 on Piate 29 is taken from a section of a colony sbowing partly 

 very fiat and ratber smooth individuals, which show very plainly the 

 sbape of a cocks-comb given by Haeckel as characteristic for Z. cram- 

 hessa , partly however also conical individuals with circular section 

 and projectiug spicules. Sometimes the surface is quite smooth and 

 then you may see bere and there big spicules glistening in the ligbt but 

 lying parallel to the surface, sometimes the surface seems to be smooth 

 if you touch it moving the finger in an «oral- direction, however it ap- 

 pears to be rough if moving in the opposite way. But there are also 

 specimens to be found in which many rods protrude as far as in the ty- 

 pical L. aspera. Haeckel says that in the latter the angle between the 

 rods and the axis of the Sponge is 45o. As sbown in fig. 3 (Piate 29) 

 there the angle is about 45^ also. In the variet}' typica however this 

 angle may become greater the size varying also immensely. According 

 to Haeckel L. aspera varies between 10 and 40 mm (»solitäre Form«) 



1 "Der Körper der Personen ist nämlich ganz Constant blattförmig zusammen- 

 gedrückt" .... 



