NATURE AND AFFINITIES OF THE SPONGES. l6l 



afforded by the character of the test, which in the former instance consisted 

 of two or more intercommunicating chambers in place of the single one 

 only possessed by the last-named type. Concerning the internal structure and 

 significance of the interconnecting cavities in GastropJiysema, however, a far 

 different and most remarkable interpretation was arrived at. The different 

 chambers were in fact declared by Haeckel to be set apart for the per- 

 formance of special and independent functions. Affirming that ciliated 

 bodies or gastrulse, similar to those of the sponges, were found only in the 

 proximal or basal of the two chambers of G. dithalanihtvi, he relegated to 

 this cavity the function of reproduction, and bestowed upon it the special 

 title of the " brood-chamber " or " uterus." The succeeding or anterior of 

 the two cavities he declared to be a true stomach, communicating with the 

 external world through the medium of the terminal aperture designated 

 by him the mouth. The list of structural complexity, however, by no 

 means ended here. Among the ordinary flagellate cells of the so-called 

 stomach-cavity, Haeckel observed, or affirms to have observed, certain ovate 

 cells of a special nature, pronounced by him to be of a glandular character ; 

 these he accordingly figured and described as gland-cells, " Driisenzellen." 



Had Professor Haeckel's observations and interpretations concerning this 

 newly introduced group of the Physemaria been confirmed, HalipJiysenia 

 would undoubtedly have to be accepted as a sponge structure in its simplest 

 known form, while in GastropJiysema a complexity of organization would be 

 superadded forbidding its correlation with either the sponges or the ordinary 

 Ccelenterata. As a matter of fact, however, the evidence more recently 

 adduced has tended to raise the gravest doubts concerning the very existence 

 even of such an organic group as the so-called Physemaria of Professor 

 Haeckel. 



Haliphysema Ttmianozviczii and GastropJiysema {Squamidina) scopula have 

 both been proved to be varieties of one form, and instead of a simple sponge, 

 as first described by Dr. Bowerbank, to be an arenaceous or test-bearing 

 foraminiferal type. This interpretation, first suggested by Mr. Carter, has 

 been fully established by the present author in a paper, with accompanying 

 illustrations, published in the 'Annals and Magazine of Natural History' 

 for July 1878. The account and illustrations there given were derived from 

 the examination of living specimens collected in the Channel Islands, and 

 which in their healthy condition exhibited their true nature by the emission, 

 from the terminal aperture of their tests, of extensive reticulate pseudopodia 

 exhibiting circulatory currents, comparable in all ways to those of the 

 ordinary Foraminifera. By a careful investigation of that portion of the 

 organism contained within the test, it was likewise shown that there was no 

 trace whatever of a lining layer of flagellate cells, as asserted by Professor 

 Haeckel, all, throughout, being simple homogeneous or more or less granular 

 sarcode. A similar Foraminiferal interpretation has been arrived at by 

 Professor Mobius, with respect to a new species, HalipJiysema capitulatum, 

 examined by him in the living state at the Mauritius, and in which pseudo- 



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