26 THE VOYAGE OF H.M.S. CHALLENGE R. 



few hours I was examining them ; in this case they are Ammoeonidse. I pointed out in 

 my Monograph that the pores of the Asconidse are often closed for a long time, and when a 

 single tubular Calcolynthus (as that of PL I. fig. 1 in my Monograph) is examined in 

 this temporarily closed state, it may be assumed to be a Physemarium (Haliphysema). 



The genus Haliphysema was first described by Bowerbank (1864) as a simple 

 sponge. 1 Carter afterwards expressed the opinion that it was not a sponge but a 

 Foraminifer, 2 and most of the later writers on the subject agree with him. But I think 

 I have sufficiently demonstrated in my Monograph of the Physemaria 3 that this latter 

 opinion cannot be proved. Bowerbank's original description is so incomplete that his 

 Haliphysema may have been either a true sponge (Ammolynthus), or a Physemarium 

 [Prophysema), or a Foraminiferous Monothalamium (Rhabdammina, Technitella, &c). 

 The most careful examination of the original dry specimens (should they still exist) 

 cannot decide this question. It can only be decided by the accurate examination of 

 living or well-preserved specimens from the same locality. 



True monothalamous Foraminifera, similar to Haliphysema, — and so similar that 

 they appear externally identical, — have been carefully examined in the living state, and 

 described by Mobius 4 in 1874. I myself repeated these observations in 1881 in the 

 coral reefs of Ceylon, where the same forms are very common, and I can completely 

 confirm the correctness of the beautiful figures and accurate descriptions of Mobius. But 

 the striking similarity of the simple tubular organism, described by him as Haliphysema 

 tumanowiczii, and of the true Physemaria described by me as Haliphysema 

 primordiale, &c., 5 is merely external. The inner cavity of the first is filled up simply by 

 protoplasma, issuing by the mouth of the tube in the form of numerous branching filaments 

 or pseudopodia. The true gastral cavity of the latter, however, is lined by a flagellated 

 epithelium of the same form as in Calcolynthus, and bears amoeboid eggs, as in this 

 primordial sponge. 



To avoid further confusion, I propose to employ the term Haliphysema 6 for that 

 monothalamous Foraminifer in the sense of Mobius, Brady, and most recent authors. 

 For the true Physemaria, however, which I described in 1876 as Haliphysema 

 primordiale, Haliphysema echinoides, Haliphysema globigerina, &c, it will be best to 

 adopt the term Prophysema. I may add the remark, however, that this Prophysema and 

 the closely-allied Gastrophysema may be indeed true Physemaria without pores, as I have 

 described them. But it may be, on the other hand, that true pores really exist in their 

 body- wall, and that they were closed only accidentally during my examination. Should 



1 Bowerbank, Monograph of the British Spongiada?, vol. i. p. 179, pi. xxx. fig. 359 ; vol. ii. p. 76 ; vol. iii. pi. xiii. 



2 Ann. and Mag. Nat. Hist., ser. 4, vol. v. pp. 309 et seq., pis. iv., v., May 1870. 



3 Jenaische Zeitschr., Bd. xi. p. 1, Aug. 1876. 



4 Mobius, Meeresfauna der Insel Mauritius, &c, I. Foraminifera, p. 72, Taf. i. 



5 Loc. cit., Taf. i.-iii. 



6 Norman, The Genus Haliphysema, Ann. and Mag. Nat. Hist., ser. 5, vol. i. pp. 26 et seq.. pi. xvi., April 1878. 



