ji 
1877. Carter, Ann. and Mag. XX. 
1878. Merejkowsky,ibid. 1. 
1878. Carter, ibid. ibid. 
1878. Norman, ibid. ibid. 
1878. Carter, ibid. 10 
1878. Sav. Kent, ibid. ibid. 
1880. Sollas, ibid. V. pag. 143. 
1880. Norman , ibid. NR 
Special description. 
The sponge on which so many different opinions exist, is for 
more as one reason a very interesting one. It belongs to that group 
of Sponges that possess a distinct shape; every specimen seems to 
be an individual, a „Person” in a Haeckelian sense. If I said 
that the T’henea has a distinet form, this is however with slight 
modifications, as one can see on Plate. I. figg. 1, 2, 3, 6 and. 
The type is the same. 
The body is to be divided into two parts viz. the trunk and 
the roots. The trunk has a globular form, on which at one or 
more places the plasma shows little conical papillae, the bases of 
the roots. 
In examining the Sponge accurately, there is to be seen a re- 
markable symmetry. In one of the well preserved specimens one 
distinguishes at a certain place a horizontal broad split and above 
this a part of the Sponge that juts out quite like a penthouse. This 
curious organ is moreover enlarged by a series of very long spicules 
(Pl. I. fig. 2). This form may be compared with a mediaeval cas- 
que. At the top of this casque you see a long bundle of spicules, 
representing, if you like, the tuft of feathers. In the figg. 5 and 
6 however I have represented other specimens that show another 
form. Instead of one, there are two (or three?) splits, with pro- 
truding penthouses. I must call to mind the figures that Oscar 
Schmidt gives of his Tisiphonia fenestrata !), showing how the sym- 
metrical: form becomes radial. The splits are not always so deep 
1) Schmidt, Spong. Meerb. Mexico II tab. X fig. 2. 
