530 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Remarkable Actinian.* — Dr. C. P. Sluiter corrects an error which 

 he committed in an article on two remarkable Gephyrea in vol. xlviii. 

 (p. 233) of the Nat. Tijdschr. voor Nederl. Indie. He now sees that 

 JJiphthera octoplax is an Actinian. He urges that ho had never before 

 seen an Actinian of the kind, and that no one who saw it alive would 

 hesitate to call it one of the Phascolosomata. The anterior end of the 

 body looks like a proboscis and acts energetically and not slowly. The 

 histological characters of the integument are much like those of a Sipun- 

 culid. The creature should, apparently, be placed in the genus Edwardsia. 



Caryophyllia rugosa.j — Herr G. v. Koch has made an examination 

 of the structure of Caryophyllia rugosa. This form has especial interest 

 from the fact that it was described by Moseley as having the septa 

 arranged in octameral fashion. With this Herr v. Koch cannot agree, 

 as he finds that there are at first six septa of the first order, which are 

 followed by six of the second. Both of these sets are arranged quite 

 symmetrically. When the septa of the third order appear there is some 

 irregularity, for those in two adjoining sections appear earlier than those 

 in the rest, while, at the same time, the interjacent septa of the second 

 order grow more rapidly than their homologues in the four other sectors. 

 There are thus gradually developed eight larger septa (six of the first 

 and two of the second order), and eight smaller septa (four of the second 

 and four of the third order), so that the coral comes to look as though it 

 were octamerous. When the third cycle is complete, the number of 

 septa is again of the hexameral type, but soon afterwards eight septa of 

 the fourth order appear in the already mentioned two sectors. The 

 whole number is thus raised to thirty-two, and as this is not increased 

 the octameral type again becomes apparent. We have here, therefore, 

 an interesting example of a coral which, when adult, is regularly 

 octamerous, being in its youth six-rayed. 



Semseostomatous and Rhizostomatous Medus8e.| — Dr. E. Vanhoffen 

 describes the MedusfB of these orders collected on the ' Vettor Pisani ' 

 expedition. Of Semaeostomata, six new species are descTihed—Pelagia 

 neglecta, P. crassa, P. minuta, Clirysaora chinensis, Desmonema cliiercMana, 

 and Aurelia duhia ; seven others are revised ; and a systematic review is 

 taken of all the known species in the above genera. Of Khizostomata, 

 six new forms were discovered — Cassiopeia picta n. sp., Loborhiza orna- 

 tella g. et sp. n., Stomolophus cJiunii n. sp., Bhizostoma hispidum n. sp., 

 Mastigias orsini n. sp., and Desmostoma gracile g. et sp. n. After describ- 

 ing these forms, the author takes a systematic survey of known Ehizo- 

 stomata. The third part of his memoir is devoted to a survey of the 

 geographical distribution with which a maj) is given. The two orders 

 diifer greatly in their range. Thus in the Eed Sea, Semseostomata are 

 absent, but Ehizostomata are abundant ; on the Pacific coast of North 

 America the reverse is true. Fi'om similar facts Dr. Vanhoffen con- 

 cludes that the Ehizostomata usually prefer warmer waters, while the 

 SemfEOstomata are more abundantly represented in temperate zones. 



Siphonophora of Canary Islands. § — Prof. C. Chun reports that he 

 has discovered a considerable number of new species of Siphonophora off 



* Zool. Aiizeig., xii. (1889) pp. 47-8. f Morphol. Jahvb., xv. (18S9) pp. 10-20. 

 X Bibliotheca Zool. (Leiickart and Chun), Heft 3 (1889) 52 pp., 6 pis. and map. 

 § SB. K. Akad. Wiss. Berlin, 1888, pp. 1141-73. Ann. and Mag. Nat. Hist., iii. 

 (1889) pp. 214-46. 



