390 Mr. H. J. Carter cm Haliphysema ramulosa, 



definitively shown to be no more a sponge than the simple or 

 unbranched form, and will probably prove hereafter to be no- 

 thing more than a branched form of Squamulina scopula, as 

 I at first suggested. 



Although Prof. Schmidt had introduced the two species, and 

 the figure of //. Tumanowtczn, in his excellent work on the 

 Adriatic Sponges, on the authority of Dr. Bowerbank, it is 

 not only fair to observe, but equally significant, that it will not 

 be found in Dr. Gray's proposed " Arrangement of Sponges " 

 (Proc. Zool. Soc. May 9, 1867). Dr. Gray doubted its assei-ted 

 nature. 



In the second instance, I have been provided by Dr. Car- 

 penter with specimens of Polytrema, both simple and '' arbores- 

 cent," together with portions of the spiculiferous structure 

 accompanying them, chiefly for examination of the latter; and 

 the result of this I have found to be that, although Polytrema 

 widely differs from Squamulina scojmla and S. varians in its 

 foraminiferous characters, still the heterogeneous mixture of 

 sponge-spicules which enters more or less into the composition 

 of their tests respectively appears to me to be the same. 



While, however, the basis of the test in S. scopuJa and S. 

 varians consists of an agglomeration of siliceous sand, that of 

 Polytrema consists of calcareous matter secreted by the animal 

 itself ; and so far the basis-matei'ial of the tests differs ; but 

 sponge-spicules are alike ])resent in that of Polytrema, as 

 Schultze has already stated (ap. Prof. Allman, last No. of 

 ' Annals,' p. 373), and in that of Squamulina scojmla &c. 



The spicules differ, of course, with the kinds of sponges 

 growing in the locality from which they are sujiplied ; and 

 hence we do not expect to find exactly the same kinds of spi- 

 cules in the Haliphysema from the Gulf of Florida that we 

 find in Squamulina scojnda of the British coasts ; nor do we 

 expect to find the same kinds of spicules in the specimens of 

 Polytrema which were brought from the tropics by Mr. Denis 

 Macdonald to Dr. Carpenter. 



Thus in specimens of the spiculiferous structure taken from 

 the latter, I have observed the pin-like, spinous, and sinuous 

 spicules of Cliona northumhrica^ fragments of the lieads and 

 shafts of very large trifid spicules of a Geodia (?), together with 

 a very preponderating number of the minute stellate spicules, 

 and a few large ones like those of Tethea lyncurium, a 

 " dichotomo-patento-ternate " spicule of Dactylocalyx Bower- 

 banhiij just like that figured in plate 2. fig. 53 of Bowerbank's 

 * Brit. Sponges,' and many other kinds, mixed together, but 

 too numerous to mention individually. 



In the fragments of spiculiferous structure given me for 



