390 SUMMARY OF CUERENT RESEARCHES RELATING TO 



described by Browne as Irene, ceylonensis. The hydroid stage must be 

 referred to the genus CampanuUna van Beneden. Large numbers of 

 medusoids, agreeing with Browne's figures and descriptions, appeared in 

 a canal of braclcish Avater in Calcutta, and young colonies of hydroids 

 were reared in a bell- jar. 



A characteristic feature of the hydranth is the webbing of the 

 tentacles at the base ; the tentacles are surrounded by regular circles 

 of nematocysts ; there is a short conical hypostome. The hydroid was 

 found plentifully in association with the tube of a spioniform Polychajt. 

 The gonosome usually grows from the base of a livdrosome and contains 

 two medusoid buds. In its earliest phase the gonobome appears as a 

 tubular outg:rowth from the ccenosarc ; this tubular outgrowth is 

 a blastostyle ; the medusse arise from buds which spring from the stem 

 of the blastostyle below tbe operculum. They appear to arise in the 

 usual manner by the sinking in of an entocodon. Some account of the 

 free medusoids is also given. 



to' 



Change of Symmetry in a Polyp.* — A. Drzewina and G. Bohu 

 describe a living specimen of Stauridium ^^roductum, which showed in 

 the arrangement of its tentacles a trimerous instead of a tetramerous 

 symmetry. The tentacles developed in whorls of three, instead of in 

 whorls of four. The authors call this phenomenon, not very happily, 

 " symetrie metaljolique," and regard it as probably an adjustment to 

 the circumstances of the individual life. 



Porifera. 



New and Rare HexsBtineilids.t — Arthur Dendy reports on three 

 Triaxonida, collected by H.M.S. ' Bealark' in the Indian Ocean. The 

 first is Autocalyx serialis, a new species of a genus hitherto known only 

 by fragments of the type species {A. irregularis), obtained by the 

 'Challenger.' The second is Heterorete 'pidchra g. etsp. n., related to 

 Dactylocalyx, remarkable for the entire absence of special dermal and 

 subdermaf spicules, and, further, interesting in the presence of a com- 

 mensal or parasitic hydroid ramifying through the substance of the 

 wall, as well as of numerous Anthozoa attached to the surface. The 

 third is Sarostegia ocidata, a very beautiful and remarkable sponge, first 

 described by Topsent from deep water off the Cape Yerde Islands. 



Tetraxonids from Indian Ocean. f — Arthur Dendy deals with the 

 Homosclerophora and Astrotetraxonida, collected by H.M.S. ' Sealark ' 

 in the Indian Ocean. The collection included twenty-five species, nine 

 new. Hentschel's modification of Dendy's (1905) classification of 

 Tetraxonids is followed, which recognizes three sub-orders : Homosclero- 

 phora Dendy, Astrotetraxonida Hentschel (= Astrophora + Astro- 



* C.R. Soc. Biol. Paris, Ixxix. (1916) pp. 131-4 (1 fig.). 

 t Traus. Liun. Soc. (Zool.) xvii. (1916) pp. 211-24 (4 pis.). 

 X Trans. Linn. Soc. (Zool.) xvii. (1916) pp. 225-71 (5 pis.). 



