HYDROIDA. BALE. 301 



Busk, 1 Heteropyxis tetrasticha, (Lowenia tetrasticha, Meneg- 

 hini) 2 , and N. decussata, Kirchenpauer. 3 Of these A. 

 cymodocea is distinguished from our species (and probably 

 from all others) by the very peculiar structure of the hydro- 

 cladia, which, according to Kirkpatrick, 4 "are short, and 

 composed of five or six joints, each bearing a cupped sarco- 

 theca, and on the last joint a hydrotheca, adnate and dove- 

 tailed into the joint ; a second hydrotheca is only exceptionally 

 present." Kirkpatrick also mentions that the calycle is .1 

 mm. in length, which is about double that of N. ciliata. 

 Further, A. cymodocea is said by Busk to be an unbranched 

 species. 



N. tetrasticJia cannot be confused with N. ciliata, as its 

 hydrocladia consist of hydrothecate internodes solely, and 

 only one mesial sarcotheca occurs between every two hydro- 

 thecse. 



N. decussata has more affinity with the hydroid before us, 

 its habit, however, is very different. It has thick polysiphonic 

 stems from half an inch to an inch long, which divide quite 

 irregularly one or more times into smaller polysiphonic 

 branches, and these are continued, sometimes bifurcating, into 

 long monosiphonic branchlets which may attain two or three 

 inches in length without again subdividing. It is stated that 

 each pair of hydrocladia occupies a separate internode of the 

 branch, contrary to the condition in N. ciliata. According to 

 Kirchenpauer's figures the hydrotheca3 are larger than in most 

 species, while in N. ciliata they are almost the minimum size 

 for the family. The gonangia of N. ciliata contrast strongly 

 with those of Kirchenpauer's species, which are of the lageni- 

 form type found in Plumularia setacea. 



Locs. Off South Cape, Tasmania, 75 fathoms. 



Twenty-five miles north-east of Babel Island, Bass Strait, 

 70-100 fathoms. 



Genus KIRCHENPAUERIA, Jickeli. 



In Part I., under Kirchenpaueria producta, I have already 

 discussed the validity of this genus. There are three ways of 

 regarding it. First, it may be recognised as a distinct genus, 

 to be known as Kirchenpaueria, unless the name Diplocheilus 

 should prove to have priority a question still unsettled. 



1. Busk Report British Association for 1850, (1851), pt. 2, p. 119. 



2. Meneghini Memor. dell' Instit. Venet., 1845, p. 183, pi. xiv., fig. 2. 



3. Kirchenpauer- Abh. Nat. Ver. Hamburg, vi., 1876, pp. 52, 54, pis. 

 ii., iii., and vii., fig. 24-24c. 



4. Kirkpatrick Sci. Proc. R. Dublin Soc. (n.s.), vi., 1890, p. 610. 



