816 SUMMARY OF CUERENT RESEARCHES RELATING TO 



Coelenterata. 



Adamsia palliata.* — M. Faurot has studied Adamsia palliata, 

 which has been long known to have a symbiotic relation to Eupagurus 

 prideauxi. Great as may be the alteration in the form of an adult 

 Adamsia its anatomical structure is morphologically the same as that 

 of other Actiniae, and especially of Sagartia parasitica. The defor- 

 mation undergone by the animal is due to the considerable expansion 

 of the foot, which affects the lower part of the column ; this expansion 

 is so considerable in an adult animal as to bring the foot and the 

 wall of the column into parallel planes for a considerable distance ; 

 from this it results that the true gastric canals are formed by the 

 elongation of the folds in a horizontal direction. Fertilization takes 

 place within the body, and a gastrula is formed ; fixation takes place 

 when there is a larva with eight tentacles. The Actinia, on attaining 

 a certain size on the inner edge of the shell of a Gastropod, extends 

 to right and left in such a way as to follow its outer border without 

 covering it in any way, and it thus excellently shelters the Pagurus. 



Porifera. 



CcBlenterate Nature of Sponges.f — Dr. "W. Marshall defends the 

 coelenterate nature of sponges against Schultze, SoUas, and others ; he 

 thinks that there is no phylogenetic connection between the Flagellata 

 and the flagellate cells of sponges, but that both are adaptations. He 

 discusses the characters of the radial symmetry of the Coelenterata, 

 and appears to regard it as being mostly due to their mode of life. He 

 insists on the ancestors of sponges having been at least diploblastic, 

 and, apparently, radially symmetrical ; they had an oral orifice and a 

 gastric cavity from which the gastric canals passed off centrifugally 

 to open to the exterior after passing through the ectoderm; such 

 creatures are, in his judgment, true Coelenterates. 



Circulation in Spongida.t — Mr. H. Carter makes a further con- 

 tribution to this subject. In a former communication, from a study 

 " of the minute portion of Spongilla developed from a statoblast," it 

 was inferred that the water entered through the holes of the investing 

 membrane to the so-called cavities of this membrane, and thence into 

 the ampullaceous sacs ; during an interval of about fifteen minutes 

 there is a cessation of the circulation, the tubular process of the 

 vent is retracted ; after this interval the process is again pushed out, 

 and the water passes from the ampullae through the large canals of 

 the excretory system to the vent, and so to the exterior ; it was not 

 plain, however, how the carmine particles got from the cavity of the 

 investing membrane through the parenchyma. In two new species, 

 Geelongia vasiformis and Hircinia intertexta, which are briefly described, 

 the arrangement of the fibres and excretory canals is different ; in 

 the former they are perpendicular to the planes of the wall, in the 



* Comptes Rendus, ci. (1885) pp. 173-4. 



t Jenaisch. Zeitschr. f. Naturwiss., xviii. (1885) pp. 868-80. 



t Ann. and Mag. Nat. Hist., xv. (1885) pp. 117-22 (1 pi.). 



