Wright — On a New Genus and Species of Sponge. 755 



minent, and the bodies of the rings will be, as it were, more deeply 

 sunk. In both these cases the horny framework is of a more or less 

 evenly latticed character, the longitudinal lines of the lattice being 

 very prominent. 



The head portion, in its natural state must, I think, present a more 

 or less spherical form, perhaps slightly flattened on the summit, with an 

 indication of being divided into four nearly equal parts — the open 

 space between these leading into the body cavity of the sponge. In some 

 of the specimens the head portion nearest to the stem seems to have 

 been formed of a somewhat denser framework than the upper portion, 

 so that while being pressed this upper portion has been fractured 

 across [vide fig. 1). The framework here is of a densely reticulated 

 kind, in appearance reminding one of the reticulated network of the 

 intracapsular sarcode in Thalassolampe, or of the tissues met with in 

 some Echinoderms. 



Kallispongia Arcluri, sp. nov. 



The description of the genus will, for the present, serve for the 

 species ; specimens vary from two to three millimetres in height. 



Localities — growing on the fronds of various species of Floridese ; 

 gathered on the coasts of Australia by Professor "W". H. Harvey, about 

 1854. 



The beauty and novelty of this little sponge — the largest specimens 

 measure but three millimetres in height — must plead my excuse for 

 publishing a description of a form that may possibly turn out to be but 

 a very young stage of some other species. 



It is true that it is by far the smallest of all known keratose 

 sponges, but I do not think that its size necessarily militates against 

 the possibility of its being a good species. Why should there not be 

 very minute keratose as well as very minute calcareous sponges ? and 

 although I did once before, -'"perhaps somewhat prematurely, describe a 

 young stage of a siliceous sponge, now that its mature form is well 

 known, I perceive that the difference between the young and adult 

 form has not been so great as to suggest the idea of there being a 

 change or metamorphosis, such as one might a priori\^yQ expected, in 

 the group of the sponges. 



Kallispongia Archeri appears to me too to have a rather fixed and 

 definite physiognomy, and I can easily fancy its going through all the 

 phases of its life history — this being the persona-stage, amid the 

 thallus of its fostering alga — after the manner of some of the mi- 

 nute calcareous sponges described by Haeckel. 



One very marked variety of stem outline (fig. 3) I have met 

 with ; it ^orms a very exquisite microscopical object. The stem puts 

 one in mind of the string of frustules of a Melosira or of Didymoprium 



Quarterly Journal of Microscopical Science, January 1870, p. 1, PI. 2, 



