786 PROF. A. DENDY AND MR. R. W, H. ROW ON 



GENERA AND SPECIES " INCERT^ SEDIS." 



Genus 51. Sycaltis Haeckel [1872] (emend.). 



Diagnosis ? Canal system sy conoid (?). Skeleton of the chamber 

 layer confused. 

 The sense in which we employ this genus is obviously quite 

 diflerent from that in which it was used by Haeckel, who based 

 it upon the presence of triradiate and quadriradiate spicules and 

 the absence of oxea. Most of the species assigned to it by him 

 have been relegated to other genera, but his description of the 

 undermentioned sjDecies appears to indicate that it possesses 

 characteristics separating it widely from any syconoid sponge 

 of normal structure, and therefore, although there seems to be 

 some similarity between this sponge and Leucascus, we prefer 

 to consider it as '•'• incertce, seclis'^ rather than to assign any 

 definite position to it in our classification. It may be related to 

 Anamixilla. 



The only known species is : — 



1. S. PERFORATA Haeckel. 



Sycaltis perf or aia Haeckel [1872]. 



The following species are so inadequately known as to render- 

 all attempts to identif}^ them ineffectual : — 



Ute viridis 0. Schmidt [1868]. 



Medon harhata Duchassaing and Michelotti [1864]. 



Medon imherbis Duchassaing and Michelotti [1864]. 



The following species have been referred to without de- 

 scription : — 



Grantia striatida Bowerbank MS., referred to by Bowerbank 

 [1864-1882, vol. i. p. 233]. 



Leucogyjysia algoaensis Bowerbank MS., referred to by Bower- 

 bank [1864-1882, vol. i. p. 166]. 



Ute papillosum O. Schmidt, referred to by Gray [1867]. 



(We have not been able to discover any reference to a 

 species of this name in any of Schmidt's papers, and think 

 that Gray's reference is probably a misprint for Ute 

 capillosum 0. S.) 



LIST OF REJECTED GENERIC NAMES. 



The following list includes all the generic names that have, so 

 far as we are aware, been applied to calcareous sponges, but which 

 we have not made use of in this paper. Many of them have been 

 used in various senses by different authors, and in such cases all 



