780 SOME NEW AND RARE HYDROIDA IN THE AUSTRALIAN MUSEUM, 



of which only the former bear hydrothecae. Hydrothecse cup- 

 shaped, slightly expanded upwards, adnate up to the margin, 

 aperture at right angles with the pinna. Sarcothecse bithalamic, 

 canaliculate, slender at the base and moveable, one below each 

 hydrotheca and one on each side above it, one between every two 

 hydrothecse, on the intermediate internode, two at the base of each 

 pinna (one in front of the axil and one behind), and one on the 

 lower part of each stem-internode. 



Gonosome unknown. 



Hab. Lyttleton, N,Z. (von Lendenfeld). 



This species is very closely allied to P. setacea in most respects, 

 including the peculiar mode of branching, but is a little paler in 

 colour, with the pinnse more lax and less divergent. The hydro- 

 thecse are proportionately broader at the base and less expanding 

 upwards, while the pinna is more abruptly swollen below the 

 hydrothecse, giving the species a somewhat distinctive aspect. 

 Another characteristic of P. turgida, is the presence of a sarco- 

 theca behind each axil as well as in front. An American Hydroid 

 identified by Clarke* with Plumularia setacea resembles the present 

 species in these particulars, but is very much larger in growth, 

 measuring sometimes as much as 300 mm. 



PLUMULARIA CALICULATA, n.sp. 



(Plate XX., figs. 9-10). 



Hydrocaulus monosiphonic, about J inch high, pinnae alternate, 

 not close, one borne near the summit of each internode, divided 

 into alternate long and short internodes, of which only the former 

 bear hydrothecse. Hydrothecse cup-shaped, shallow, slightly 

 expanding upwards, adnate up to the margin, aperture nearly at 

 right angles with the pinna. Sarcothecae bithalamic, canaliculate, 



*Hydroids of the Pacific Coast of the United States, south of Vancouver 

 Island, &c., S. F. Clarke. Trans, of the Connecticut Academy of Arts and 

 Sciences, Vol. III., Part 2. 



