912 ADDENDA TO THE AUSTRALIAN IIYDROMEDUSjE, 



there is one Trophosome to each Internode, but sometimes there 

 are two, close together. The Peduncle consists of two spherical 

 parts, with incisions dividing them from the Hydrotheca, each 

 other and the Internode of the stem. Strictures in the Ccenosark 

 tube correspond to these. The Hydrotheca is cup-shaped, bi-lateral, 

 symmetrical, the outer margin a little higher than the inner, so 

 that the oval aperture looks obliquely forward. 



The Ccenosark of the stem does not contain the highly colourable 

 cells found in the Hydrorhiza. 



The alimentary zooids possess 10-15 stout tentacles and a short 

 proboscis, but otherwise appear similar to other Campanulariang 

 or Leptomeduse-Polyps. There is a decided "floor" to the 

 Trophosome. 



Locality. — Port Phillip. 



6. GENUS. LAFOEA. Lamourroux. 

 ISa (232). L. CYLINDRICA. Nov. Spec. 

 Plate XL., Figs. 4, 5. 



Ciamician (1) described a species of this genus as L. Parasitica, 

 from the Adriatic. I have recently obtained a similar Lafcea, 

 which, however, is not identical with Ciamician's species. 



The Hydrorhiza is creeping, and closely adnate to the stem of 

 other Hydroids, mainly Sertularians. It appears very small and 

 slender, and is not smooth. It runs in a straight line, and keeps 

 to the same side of the Hydroid and is attached throughout, as is 

 also the case with L. Parasitica. From this creeping stem large 

 Hydro thecse arise, which are borne on very short and extremely 

 narrow peduncles. (Fig. 5.) The Hydrotheca is mainly 

 cylindrical and thin walled, large as in L. Parasitica. The margin 

 is recurved so that it attains a trumpet shape. Near the 

 bottom, which appeal's semi-spherical we find a perforated disc, 

 forming a ring near the base of the Hydrotheca. Although the 

 Trophosome of Lafcea is considered always to be destitute of a 

 floor, I do not hesitate to consider this species as a true Lafcea. 



(1.) T. Ciamician Ueber Lafcea parasitica, n. sp. Zeitschrift fur 

 Wisscnschaftliche Zoologie. Baud XXXI11. Seite 673. 



