REPORT ON THE KERATOSA. 11 



out the internal organisation of the Porifera and applied it to systematic purposes. 

 Prof. Schulze ^ characterises his family of Spongelidse primarily by the structure of the 

 soft parts ; in Dr. Marshall's diagnosis of Dysideidse not a single word is devoted to this 

 character. Does he regard it as devoid of any systematic importance 1 This seems to be 

 the case, but the grounds for this opinion are not to be found in Dr. Marshall's paper, 

 and without this the paper in question is of very doubtful profit for systematic know- 

 ledge, and this is the case with every paper on the Keratosa based on specimens insuf- 

 Jiciently preserved for anatomical exa.mination. Such papers, if from the pen of authors 

 of talent, may still contain something of general interest, and this is in a high degree 

 the case with regard to Dr. Marshall's memoir on Dysideidte and Phoriospongise, but just on 

 that account it is the more to be regretted that from a systematic point of view this memoir 

 only renders the systematic chaos relating to the group Keratosa still more impenetrable. 

 In the Bemerkungen liber die neue Gray'sche Hornschwammgattung lanthella" 

 by Dr. Flemming, spongiological literature has been enriched with a new and very valu- 

 able contribution to our knowledge of the properties of the horny skeleton. Dr. Flemming 

 has stated — and, as I before remarked, I can but confirm his statements — that the fibres 

 of lanthella flabelliformis and lanthella basta contain true cells between the laminos 

 of their walls. The specimens of both (?) the sj)ecies obtained and examined by Dr. 

 Flemming were dried, and thus he has not been able to decide the question as to whether 

 lanthella is really to be referred to Porifera. He believes, however, that, if so, a very 

 isolated place in the group is to be assigned to this sponge (" Es scheint mir zuniichst 

 nicht viel iibrig zu bleiben, als sie bei den Spongien, aber auf einem sehr isolirten Platze 

 einstweilen stehen zu lassen ").^ Dr. Flemming's suggestion is to be regarded as quite 

 natural, if we remember that his paper on lanthella appeared in the year 1871, i.e., 

 five years before the important discovery of spongoblasts by F. E. Schulze ; but at 

 present one may perhaps form another opinion as to the systematic importance of the 

 peculiarity in question. The gist of the matter consists in the fact that each horny fibre 

 is the product of cellular elements; and whether the spongoblasts, after having accomplished 

 one part of the work, recede before the developing fibre in order to partake in its further 

 growth, or remain in their former places in order to be buried in the horny substance 

 secreted by younger spongoblasts, seems to me to be of secondary significance. 

 Dr. Flemming demands for lanthella a quite isolated place amongst the Keratosa ; 

 again, Gray, Carter, and Hyatt, on the ground of characters of undoubtedly less 

 value, of characters to which in other instances we should apply only a generic if 

 not a specific significance, are inclined to regard it as the representative of an inde- 

 pendent family. For my own part, I must confess frankly that the systematic importance 

 of the peculiarity we are speaking of is rather ambiguous. For though, as before 



1 Zeitschr.f. wiss. Zool, vol. xxxii. ■^. 153. - Wiinhmj Verhandl., N. F., Bd. ii. 



' Loc. cit., p. 7 ; comp. also p. 6. 



