

so-called u Farringdon Sponges" 27 



modified tri- or quadriradiate which extended into the adjoin- 

 ing portions of fibre, but have been cut away by the sec- 

 tioning. Still the structure is very badly preserved ; but 

 whatever the spiculation may hereafter in a more favourable 

 specimen prove to be, I can only regard it, from the presence 

 of the triradiates &c, as allied in spiculation to the foregoing 

 species, and therefore in no way connected with the Echino- 

 nemata, as suggested by Prof. Sollas (No. 9, p. 359), or with 

 the Alcyonida3, as proposed by Dr. Steinmann (No. 13, 

 p. 177). Indeed the indistinctness arising from a partial 

 dissolution of the spicules, rendered, as before stated, still 

 more deceptive by the thinness of the section, led me to cha- 

 racterize it formerly as a ?Lithist id-branched " in my u Note 

 on the Farringdon Sponges " (No. 11, p. 433), which, now 

 that I am better informed in all respects regarding these 

 fossils, must be repudiated in favour of Prof. ZitteFs original 

 and sounder views. 



The result of a similar examination of Oculospongia dilatata 

 from Farringdon (another of ZitteFs genera) shows that its 

 fibre also is composed of a chain of triradiates, but apparently 

 without any large axial spicule, while that of Peromelia 

 cylindrica in Prof. ZitteFs slide evidently possesses one ; and 

 the echination produced by the triradiates outside, so faithfully 

 represented in his published illustration (Handbuch der Palae- 

 ontologie, p. 190, fig. 107), will be easily distinguished from 

 that of a siliceous Echinonematous sponge, when the new 

 species of Calcisponge from South-west Australia, to which I 

 have alluded, comes to be described, in which the peculiarly 

 formed colossal spicules of the fibre internally are bound 

 down by a number of smaller equiarmed triradiates whose 

 arms project externally. 



While, however, there are spiculations among ZitteFs fossil 

 Calcisponges which indicate a more remote alliance with exist- 

 ing Calcisponges than others, there are some which have not the 

 least resemblance to them in this respect ; and hence, if we 

 are to maintain the latter among the former, it must be by some 

 other evidence than that of the presence of tri- or quadri- 

 radiates. I allude to the genera Stellispongia and Pharetro- 

 spongia, in both of which the fibre is entirely made up of 

 acerate or monactinellid spicules u dove-tailed " in between 

 each other so as to form an anastomosing, cord-like, reticulated 

 structure. In the former the spicule appears (for the minute 

 structure of the specimen is clouded, and therefore not well 

 defined) to have been undulating, and in the latter (where it 

 is clear) to have been slightly curved ; but both were smooth, 

 fusiform, and pointed at each end, although the general aspect 



