1908,] CAPE VEEDE ISLANDS SPONGES. 763 



kleiner sincl und mir eine Schenkellange ron 0-04-0-06 mm. bei 

 einer Dicke von 0-003-0-005 mm. erreichen. Ausserdem ist die 

 Innenseite der Rohren bei L. nanseni stets mit Papillen besetzt, 

 dagegen bei L. canariensis nur bei der Yarietat j^ai^illO'ta H." 



The measui-ements which he gives for the spicules of L. nanseni 

 are: length of rays 0-113 to 0-145 mm., thickness at base 0-008 

 to 0-014 mm. This makes the spicules, as Breitfuss points out, 

 nearly three times as large as in L. canariensis. I have found, 

 however, a series of specimens which completely links up the 

 two forms in this respect. There is one other slight difference 

 between the two forms which Breitfuss does not mention in his 

 comparison : in Z. canariensis, Haeckel says that the apical rays 

 of the quadriradiates are straight and are sometimes longer, 

 sometimes shorter, than the facial rays ; whereas in L. nanseni 

 Breitfuss states that the apical rays are sUghtly curved and are 

 usually only half the length of the other rays. In this character, 

 too, I have found specimens intermediate between the two forms. 

 Since papillae were present on the inner surface of the Ascon- tubes 

 in some of Haeckel's Ascallis canariensis, the presence of these 

 structures ia L. nanseni is not a specific distinction between the 

 two forms. 



L. nanseni appears to me to resemble a sponge described by 

 Schuffner [22] under the name of Ascaltis comjxtcta, even more 

 than it does the original L. canariensis. A. comjxtcta, which was 

 found off Mauritius, has regular triradiates and quadriradiates 

 with rays reaching a maximum length of 0-12 mm. and a maximum 

 thickness of 0-012 mm. The apical rays of the quadriradiates 

 are 0-084 mm. long, have a basal thickness of 0-009 mm., and are 

 sharply pointed and slightly bent at their exti'emities precisely as 

 in L. nanseni. The ratio of the length to the thickness of the 

 rays is slightly less than in L. nanseni, being usually less 

 than 10 to 1 and sometimes as low as 7 to 1. Schuffner 

 separated his sponge from Haeckel's A. canariensis because 

 (1) it had no papillae on the inner su.rfaces of the Ascon-tubes, 

 and because (2) of the different shape of the apical rays of the 

 quadriradiates. With regard to the latter point, I have, as stated 

 above, found specimens intermediate between the two forms, and 

 have also found much variation within the limits of the same 

 specimen. And as for the papilla?, it is truly remarkable that 

 whereas one of Schuffner's reasons for separating his sponge from 

 A. canariensis was that it never had these structures, Breitfuss 

 separated his sponges from A. canariensis partly on the ground 

 that they always did have the papillae. This affords a very good 

 illustration of the kind of confusion which must necessarily arise 

 if attempts are made to utilise structures, which are known to be 

 indifferently present or absent within one species, as specific 

 distinctions between that species and other members of the genus. 

 It therefore appears that this Ascaltis comjxtcta is not distinct 

 from either L. nanseni or A. canariensis, and I include it in the 

 species L. canariensis. 



