706 SUMMARY OF CURRENT RESEAKCHES RELATING TO 



It differs from Hydractinia in having several verticils of tentacles, 

 and in not having globular clnsters of thread-cells in place of tentacles 

 on the blastostyle. Some of tlu species have a wide distribution over 

 the globe, and there are evident similarities between the Australian 

 and East Indian faunas. The list includes Plumularia setacea and 

 Cuspidella costata, both British species. The former has been also 

 recorded from North America, Australia, and New Zealand ; the latter 

 from North America. 



New Type of Siphonogorgid Alcyonarian.* — Jas. J. Simpson 

 describes a beautiful and aparently unique Alcyonarian — one of the 

 Siphonogorginse — from deep water in the Indian Ocean. He names it 

 At/aricoides alcocM g. et sp. n. It is an upright mushroom-shaped 

 colony, with a densely spiculose trunk and a zooid-bearing " pileus." 

 The zooids are introversible within projecting verruceae — cylindrical 

 extensions of the trunk canals, the upper portions of which are expanded 

 peripherally into octagonal disks containing eight canals, corresponding 

 to the eight compartments formed by the retractor muscles. The 

 anthocodite are borne on somewhat slender stalks, the elastic walls of 

 which are continuations of the upper walls of the disks. The tentacles 

 are simply folded over the wide oval disk. The spicules are irregularly 

 echinate, straight and curved spindles, with some approximation to 

 scaphoids, besides single clubs and " hockey-clubs." 



Axis of Gorgonidifi.f — Alfred Schneider comes to the following 

 conclusions : (1) The axial epithelium of von Koch is not ectodermic, 

 but is the endoderm lining the axial cavity of the polyp ; (2) the 

 formation of the axis is due not to this axial epithelium, but to chalico- 

 blasts and spongioblasts ; (3) spongioblasts occur in corals as in 

 sponges ; (4) there are transitions between Scleraxonia and Holaxonia, 

 so that this subdivision has little warrant. 



Porifera. 



Studies on Dendroceratida.J — E. Topsent prefers the term Dendro- 

 ceratida instead of Hexaceratida, excludes the family Halisarcidas, and 

 recognises three families : — 



1. Darwinellidae : Hexadella, Aphjsilla, Darwinella, Dendrilla, 



Megalopastas. 



2. Pleraplysillidge, fam. n. : Igernella g. n., Pleraplysilla g. n. 



3. Ianthellida? : Ianthella and Haddonetta. 



He gives diagnoses of the genera, and describes a number of new species. 



Protozoa. 



Notes on Radiolaria.§ — Thos. Robinson gives a clear introductory 

 account of the Radiolarians, summarising the most important facts in 



* Zool. Auzeig.. xxix. (1905)pp. 263-71 (19 figs.). 



t Arch. Nutur., lxxi. (1905) pp. 105-34 (2 pis). 



J Ar<-h. Zool. Exper., iii. (1905) Notes et Revue, No. 8, pp. clxxi.-cxcii. (2 figs.). 



§ Trans. Manchester Micr. Soc, 1904, pp. 44-54 (1 pi.). 



