360 Mr. E. A. Minchin on the 



III. Genus Ascandka, Hackel, 1872, emend. 



The full-grown colony has the form of a loose reticulum of tubes with 

 numerous erect chimney-like oscula. The gastral layer thrown into 

 folds, forming radial diverticula. All other characters as in Clathrina. 



With one species : 



Ascandra falcata, Hackel, 1872. 



There remain many other known species of Ascons, as, for 

 instance, the interesting forms from Australia described by 

 Carter and Dendy, to which this classification must be fitted, 

 either in its present or in a modified form, if it is to be ren- 

 dered complete ; but, as I have already said above, I defer 

 for the present any discussion as to their place in my system, 

 handling here only those species with which I am familiar in 

 the flesh. But the two interesting species which Hackel has 

 described in his genus Ascyssa deserve a few passing remarks. 

 They are peculiar for the fact that the skeleton consists only 

 of monaxon spicules, thus reminding us of the stage which 

 is transitory in Leucosolenia variabilis^ and also, as Metschni- 

 koff first pointed out, in Sycon. 



It is remarkable that no naturalist since Hackel's time 

 appears to have met with these sponges, a peculiarity which 

 they share with many other striking forms of animal life 

 discovered by Hackel. Considering the precise locality given 

 by Hackel in the case o{ Ascyssa troglodytes, " on colonies . . . 

 of Astroides ca^cularis ... in the Blue Grotto of the Island 

 of Capri . . . and in other caves of the island," and, further, 

 his description of it as " small, delicate, brown tubes, which 

 were seated, some singly, some together in clumps, on dead 

 colonies of Astroides^'' it is astonishing that it should not 

 have been found, so far as I am aware, up to the present by 

 the energetic naturalists of the Zoological Station at Naples. 



Carter's handwriting, the name '■^Soleniscus variabilis, H." The monaxons 

 vary from minute to those of very large size, and the first specimen — 

 fig. 6 of Bowerhank — is further remarkable for the great number of irregu- 

 lar triradiate spicules it contains. In fact, it might be said of this speci- 

 men that abnormality has become the rule, and regularity the exception, 

 in respect to its triradiate spicules, and it appears to be from this speci- 

 men that Bowerbank took his figures of the spicules. Nevertheless 

 enough regular triradiate systems can be found to characterize the sponge 

 beyond all doubt, and the other two specimens are perfectly normal 

 culonies of varmhilis. In view of the fact that these specimens came 

 originally from the Brighton Aquarium, it would be interestuig to see how 

 far the pectiliarities of spiculation are due to life in the aquarium. Com- 

 pare Bidder's account of " Sycon raphanus, var. aquariensis, nova," from 

 the Naples Aquarium (Quart. Journ. Micr. Sci. n. s. xxxviii. p. 10). 



