1873.] DR. J. S. BOWERBANK ON THE SFONGIADjE. 21 



From this case, and from other similar experiences, it appears 

 that, if we wish to find the living representatives of the beautiful 

 series of the chalk sponges, we must search for them among the 

 multitudinous singular forms of the recent animals that abound in 

 Australian seas. 



Ciocalypta Tyleri. (Plate IV.) 



Sponge massive, sessile, composed of numerous, closely packed, 

 attenuating, penicillate branches rising perpendicularly from a com- 

 mon base ; branches gradually attenuating, apices rather acutely 

 terminated, entirely closed, deeply furrowed or corrugated. Oscula 

 simple, dispersed over all parts of the sponge. Pores inconspicuous, 

 dispersed. Dermal membrane smooth, abundantly spiculous ; spi- 

 cula acerate, small and slender, dispersed, closely felted together over 

 the whole surface of the membrane, Avith a few skeleton- or larger 

 spicula intermixed. Skeleton-spicula acerate, rather variable in 

 size. 



Colour in the dried state cream-white. 

 Hab. Port Elizabeth {Capt. Charles Tyler). 

 Examined in the dried state. 



I received two specimens of this interesting species from my friend 

 Capt. Charles Tyler, who obtained them from Port Elizabeth. The 

 one figured is the smallest of the two ; but it is the most characteristic 

 in its growth and general external appearance, which, in both spe- 

 cimens, so closely resemble those of the British species in its early 

 stage of growth, that it would be impossible to separate the two 

 species if it were not for the differences that exist in their organiza- 

 tion. The structure of the skeleton of C. Tyleri is in principle 

 exactly that of C. pie7iicillus. There is the same central column in 

 each of the penicillate organs, with numerous short pedicels of closely 

 compacted spicula radiating from it at right angles to the axis, their 

 distal ends diverging at various angles over the inner surface of the 

 dermis ; but their mode of disposition is not nearly so regularly ele- 

 gant as in the British type species. Although so closely resem 

 bling each other in external form, there is no difficulty in discrimi- 

 nating the two species by their anatomical characters, the forms of 

 their respective skeleton-spicula at once affording an unerring means 

 of separation, those of C. penicillus being fusiformi-acuate, while 

 those of C. Tyleri are acerate. The dermal membrane also of the 

 former species has its spicula fasciculated in the form of a regular 

 and beautiful reticulation, while the spicula in the latter species are 

 irregularly dispersed and closely felted together on the surface of the 

 membrane. The inhalant and exhalant systems are the same in 

 each species. 



This species is especially interesting, not only from the singularity 

 and beauty of its anatomical structure, but from its exceedingly close 

 resemblance to our British species, although so widely separated 

 from it as regards locality. The British type specimen of the 

 genus, as figured in vol. iii. pi. xiii. fig. 2, 'Monograph of British 



