596 THE AUSTRALIAN HYDROMEDUS^E, 



Locality : Port Jackson, rare, I found this species only once on 

 the bottom of a yacht in March 1884, and named it after the 

 owner of the boat. 



Season : Meclusostyles in March. 



II. SUB-FAMILY. TUBULARIN^E. 

 The Polyps possess two verticils of filiform tentacles. 



43. GENUS TUBULAPvIA. Linne. 



Medusostyles bud on tentacular processes on the oral part of the 

 Hydranth. The first stages of the development of the ovum are 

 passed through within the Medusostyle, which remains attached to 

 the Hydranth all the while. The Medusostyles are more or less 

 rudimentary. 



Stems simple or branched, rooted by a filiform stolon, the 

 whole invested by a chitinous Perisarc ; Polyps flask shaped with 

 two verticils of filiform tentacles. The oral short and surround- 

 ing the proboscis, the aboral long and forming a circle near the 

 aboi'al end of the Hydranth. 



The structure and development of many species has been 

 studied by Hamann (1), Jickeli (2), Ciamician (3), and Weis- 

 mann (4). 



The statements regarding the embryology differ to a great 

 extent, Ciamician (I.e.) supposing the Gastrula to be formed by 

 invagination and not by delamination as the other authors suppose. 



The tissue is similar to that of other Hydroids. The viscei'al 

 membrane (subepithel of the Entoderm) acquires a higher 

 developement and forms a sort of internal skeleton. 



(1) O. Hamann. Der Organismus der Hydroidpolypen. Jenaische Zeit- 

 schrift, Band XV., Seite 510. 



(2) C. Jickeli. Der Bau der Hydroidpolypen II. Morphologisches Jahr- 

 buch. Band VIII., Seite 580. 



(3; Ciamician. Ueber den feineren Ban und die Entwickelung you Tubu- 

 laria mesembryantbemum. Zeitschrift fur wis. Zool. Band XXXII. 



(4) A. Waiamann. Die Entstehung der Gesehleehtszellen bei den Hydro- 

 medusen Seite 127-128. 



