Further Notes on Australian Hydroids. 100 



KiRCIIENPAUERIA MIRABILIS, Alllliau, Sp. 

 (Plate VI., figs. 4-7.) 



Diplocheilus niiraddis, Allmau, Challenger Report on Hydroida, 

 part i., p. 48, pi. viii., tigs. 4-7. 



Hydrocaulus about two to three inches in height, monosiphonic 

 or slightly fascicled, sometimes sparingly branched ; stem-inter- 

 nodes long, pinnse alternate, not close, one or two on an internode 

 of the stem, a hydrotheca on each internode of the pinnae, joints 

 of stem and pinnjB very oblique. Hydrothecte nearly parallel 

 with the pinna in their proximal portion, distal part curved 

 upwax'ds, aperture circular, margin free, widely expanded ; front 

 wall of hydrotheca deeply inflected immediately below the lip, 

 the inflection forming an intrathecal ridge which extends rather 

 more than half across the cavity of the cell ; external sinus 

 caused by the inflection completely filled up with homogenous 

 perisarc. A single sarcotheca below each hydrotheca, fixed, 

 erect, upper portion forming a nearly circular concave shield, 

 facing the hydrotheca. A sarcostyle in the angle between the 

 back of each hydrotheca and the pinna, not provided with a 

 sarcotheca, but partly protected on each side by a narrow web 

 which connects the pinna with the back of the hydro':heca. 

 Cauline sarcothecse — one at the base of each pinna, and one or 

 two others near it, one (conical) in each axil. 



Gonangia large, free, with rounded summit, and irregular wide 

 transverse undulations, no distinct marginal ring or operrulum, 

 sporosacs two. 



Stems brownish yellow, pinnte nearly colourless. 



Hab.—^ort Phillip (Mr. J. B. Wilson) ; Grifliths' Point (Dr. 

 Haswell) ; Moncceur Island, Bass' Strait (Prof. Allman). 



This species was described by Professor Allman in the Chal- 

 kfiger Report as the type of a new genus — Diplocheilus — 

 characterised by the possession of an external calycine envelope 

 in addition to the ordinary hydrotheca. I have suggested in a 

 former paper* that the supposed external envelope was probably 

 a thickening of the hydrotheca- wall in front, similar to that which 



* On Some New aud Eaie Hydi-oida iu the Australian Museum Collection.— Proceedings 

 of the Linuean Society of New Soutli Wales, vol. iii., 2nd Series, 18S8. 



