591 SUMMARY OF CURRENT RESEAROHES RELATING TO 



marc, in which fragments of various sizes arc given off from the base of 

 the botly-wall, and grow up into new animals. It is doubtful, however, 

 whether this is a normal jirocess. Longitudinal division has also been 

 observed, though not frequently ; division may begin cither with the 

 oral disc or with the base. Here again it is not certain that the pheno- 

 menon is not due to chance external influences. In some cases, at any 

 rate, the division is not complete as far as the base. Andres has 

 observed transverse fission in an Aiptasia, but he did not think that ho 

 there had to do with a normal occurrence. In Gonadlnia the fission has 

 been observed only in young animals without developed generative 

 organs ; similar phenomena have been observed in Flahellum and Fitngia, 

 but here there were certain mori^hological differences which led Semper 

 to suppose that he had to do with an alternation of generation. In 

 Gonnrtinia there are no such differences, and at present we may rather 

 compare its mode of multiplication with that of Hydra, where all the 

 forms finally become sexually mature. Si^ecial interest attaches to this 

 mode of reproduction now that Gbtte has suggested that the young 

 Sci/phosloma has the essential structure of an Authozoon. While there 

 are, no doubt, remarkable resemblances between them, there is one 

 important difference. In Gonactinia the products of division are ex.ictly 

 alike, but the Eplujra which is set free is not the same as the sessilo 

 Scj/phostoma. Moreover, the products of Gonactinia may both again 

 multiply by transverse fission, but this is not the case with Ephjra. 

 Notwithstanding these differences we may regard this regular division 

 in Actinia) as a further suj^port to the views of Gotte as to the connection 

 between the Anthozoa and the Acalephfe. 



One case of reproduction by budding was observed in Gonactinia. 



Nature of Polyparium.* — Herr W. Haacke discusses the " tectology 

 and phylogeny " of Korotneff's Authozoan genus Polyparium. The dis- 

 coverer regarded it as a colony or corm ; Ehlers (on theoretical grounds) 

 as the portion of a person ; Haacke differs (on theoretical grounds) from 

 both, and would derive the curious form from an ordinary bilateral 

 Anthozoon. He starts from a form like a young Halcampa ; the conical 

 aboral end is replaced by a broad cylindrical basal disc, and the simple 

 tentacle wreath is supposed to be multijjle ; the organism is pulled out 

 in breadth, the oesophagus and mouth arc suii]ioscd to disappear, the 

 tentacles become short, and acquire wide terminal apertures ; and lastly 

 the basal disc is supposed to develop a number of suckers — the result 

 would exhibit the external features of Polyjxirium. The author goes on 

 to justify such an interpretation and derivation of Korotneff's genus, but 

 bis theoretical arguments are difficult to summarize. It is probably 

 better to await the possible reinvestigation of the animal itself. 



Porifera. 



Comparative Anatomy of Sponges.t— In the first of his studies on 

 the Comparative Anatomy of Sponges, Mr. A. Dendy describes Bidleia 

 g. n., and QiiasiUi7ia Norman, allied Monaxonid genera. In the former 

 the inhalent and exhaleut channels are canalicular, and the flagellated 

 chambers are provided with special inhalent and exhalcnt canaliculi, 

 while in Quasillina the inhalent and exhalcnt channels are for the most 



* Biol. Centralbl., vii. (1S88) pp. G8o-9. 



t Quart. Joura. Micr, Sci., xxviii. (1888) pp. 513-29 (1 pi.). 



