ZOOLOGY AND BOTANY, MICROSCOPY, ETC, 657 



tentacles, and is not respiratory ; actiniohsematin occurs in the ecto- 

 derm and endoderm, and is respiratory. 



A special colouring matter is found in Sagartia parasitica, different 

 from either of the above, and this too exists in different states of 

 oxidation. It is not apparently identical with that obtained by Heider 

 from Gerianthus membranaceus. 



In the mesoderm and elsewhere in Actinia mesemhryanthemum and 

 other species, a green pigment occurs which alone and in solution 

 gives all the reactions of biliverdin. 



Anthea cereiis, Bunodes hallii, and Sagartia hellis, yield to solvents 

 a colouring matter resembling chlorofucin, and all the colouring 

 matter, which in them shows this spectrum, is derived from the 

 "yellow cells" (= symbiotic algfe) which are abundantly present in 

 their tentacles and elsewhere. It is not identical with any animal or 

 plant chlorophyll, as is proved by adding reagents to its alcoholic 

 solution. 



When " yellow cells " are present, there appears to be a sup- 

 pression of those colouring matters which in other species are of 

 respiratory use. 



Porifera. 



RelationsMp of Sponges to Choano-flagellata.* — Dr. F. E. Schulze 

 criticizes the views held by Saville Kent and others, respecting the 

 systematic position of the sponge ; the so-called collared cells are 

 closely similar to certain flagellate Infusoria ; and this resemblance 

 was held by these authors as a proof of the close affinity between tlie 

 two groups. Saville Kent has brought forward other reasons in 

 support of this opinion ; in the first place he has studied the larvsB of 

 certain sponges, and has inferred from their development and struc- 

 ture that they do not correspond in any sense to a gastrula, but are 

 to be interpreted as simple colonies of Choano-flagellata ; a mature 

 sponge larva consists of a hollow sphere surrounded by a single layer 

 of collared cells, and those cases where the larva consists of simple 

 flagellate cells in one half of the sphere and granular non-ciliated 

 cells in the other half are believed by him to be later developmental 

 stages. Schulze points out that Saville Kent's statements have not 

 been borne out by other investigators, and that no one but himself 

 has seen the collared cells in the larvae ; he suggests further that the 

 so-called " larvae " are in reality nothing more than portions of 

 sponge tissue separated by teasing, which would account for the 

 appearances observed and described by Saville Kent. Even if Kent's 

 observations are correct, the fact of the development of the sponge 

 gemmule from an ovum fertilized by true spermatozoa at once sets 

 aside any possibility of a comparison with a c(dony of Choano- 

 flagellata. The discovery of a Choano-flagellate (Protospongia) con- 

 sisting of numerous collared cells imbedded in a common gelatinous 

 matrix is not, as Saville Kent thought, an argument in favour of his 

 hypothesis, since in sponges the gelatinous tissue compared by him 



• SB. K. PreuHB. Akad. WIhh. Berlin, 188r>, pp. 179 01. Sec Ann. and Mag. 

 Nat. IliBt., XV. OHHf)) pp. 3G;V77. 



