Nature o/'Haliphysema Tumanowiczii. 77 



p. 274) has considered himself justified in regarding both the 

 first and last of the four types enumerated as mere varietal 

 phases of the present species ; and by the evidence adduced 

 in this communication, so far as the characters of the external 

 test may be depended on, the two remaining ones, and more 

 especially Haeckel's Halijpliysema echinoides, are but similar 

 locally modified varieties of the same. The final solution of this 

 question, however, is necessarily dependent on the future confir- 

 mation or otherwise of Haeckel's interpretation of the internal 

 structure of these four so-called species. Truly, as already 

 insisted in my former communication, if, as he represents, 

 the internal cavities of these organisms are lined with collar- 

 bearing flagellate cells or monads*, their sponge nature is 

 undoubted, and we have in these merely remarkable isomorpha 

 or external facsimiles of the Foraminiferal type. In this case, 

 it is almost needless to remark, a new generic title will have 

 to be substituted for the sponge-form, the name HaUphysema 

 being retained for the Foraminifer. At the same time, how- 

 ever, it is requisite to remark that two at least out of the four 

 species enumerated by Haeckel, the deep-sea H. echinoides 

 and glohigerina, have not been examined by him in the living 

 state, and that therefore his delineation of their internal struc- 

 ture must border close upon, if indeed it does not belong alto- 

 gether to, the realm of the ideal. Correlating this with his 

 representation of the ciliated gemmules of the calcareous 

 sponges as consisting of an outer and inner, or epiblastic and 

 hypoblastic, cellular layer, the latter of which is now demon- 

 strated to possess no real existence, it is impossible to accept 

 without considerable mistrust his representation of a parallel 

 internal cellular layer in the minute organisms now under con- 

 sideration. Prof. Haeckel has, moreover, gone so far as to 

 say (Biol. Stud. pp. 192, 193) that examples of Halvpliysema 

 Tumanowiczii^ obtained by him on the Norwegian coast, ex- 

 hibited a similar bilaminate structure, an assertion now 

 demonstrated by both Mr. Carter and myself to have no 

 factual basis of support. 



It is to be hoped that Mereschkowsky will favour us with 



* With reference to the oral aperture of the collar-bearing monads 

 characteristic of all sponge forms, and occurring abundantly, as I have 

 recently shown, as independent organisms, Mr. Norman (7. c. p. 271) has 

 misinterpreted my views in his quotation from my communication. In 

 this he makes me characterize the collar itself as the oral or interceptive 

 organ ; by quoting a little further, however, he would have found that I 

 relegate the oral or inceptive functions not to the collar, w^hich is the 

 trap or hand to seize, but to the entire distal extremity of the bod}^ cir- 

 cumscribed by the base of the collar, the sarcode in this region being 

 softer than elsewhere and freely admitting the passage of food-matter. 



