Relationship of the Sponges to the Choanoflagellata. 365 



vascular cicatricules, the central of which is composed of two 

 confluent dots. 4. Figure from plaster cast of an impression in 

 the collection of Mr. McMurtrie. 4 a. Vertical section of one of 

 the cushions. 5. Four cushions with their associated leaf-scars, 

 from a specimen in the author's collection. Communicated by 

 Mr. J. McMurtrie. The part marked o shows the decorticated 

 condition. 5 a. Vertical section of one of the cushions. 

 Fig. 6. Lepidutlcndron Peachii, Kidston, n. sp. From the Brickworks, 

 Falkirk, Stirlingshire (nat. size). Original in the collection of 

 of Mr. C. W. Peach. 6 a. Leaf-scar, enlarged 2 diameters. 

 6 b. Leaf-scar, shown in profile, enlarged 2 diameters. 



XXXII. — On the Relationship of the Sponges to the Choano- 

 flagellata. By Franz Eilhard Schulze *. 



After Dujardin, Carter, and Lieberktihn had demonstrated 

 the agreement of certain cells of the sponge-body with Amopbce, 

 the Sponges were for a long time referred to the Protozoa. 

 More recent investigations, however, have led to the convic- 

 tion that they do not consist of colonies of homogeneous 

 individual creatures, hut of different tissues, that they repro- 

 duce sexually, and are built up out of at least two germinal 

 layers, and consequently belong to the Metazoa. 



As, however, some naturalists still continue zealously to 

 maintain the Protozoal nature of the Sponges, it becomes 

 necessary to test the arguments brought forward by them. 



Within the last few years the opinion first put forward in 

 the year 1866 by James Clark f has been defended with 

 peculiar emphasis by Carter and Saville Kent — namely that the 

 so-called collared cells of the sponges provided with a hyaline 

 membranous annular frill are to be regarded, not as epi- 

 thelial cells, but as flagellate Infusoria, and consequently the 

 entire sponges as colonies of Flagellata. Somewhat as the 

 whole of the individual animals in a colony of Ophrydium 

 are placed side by side, imbedded superficially in a common 

 gelatinous mass, so also in the Sponges the spongozoa^ as 

 Carter calls the collared cells, in accordance with the above- 

 mentioned conception, are seated as independent creatures 

 upon a common foundation after the fashion of a colony. 



It is not to be denied that there exists a great similarity 



* Translated from a separate impression of the paper in the ' Sitzungs- 

 berichte der Koniglich-preussischen Akademie der Wissenschaften zu 

 Berlin,' 1885, pp. 179-191. 



t Proc. Bost. Soc. Nat. Hist, 1860, and Mem. Bost. Soc. Nat, Hist. 1868, 

 vol. i. ; see also Ann. & Mag. Nat. Hist. 1868, ser. 4, vol. i. 



