Austnillini N 1/(1 mills. :V^ 



uiidulatioiis sli(ii'tri- and iiioir stionji;!}' itfceiituated than tiiose of" 

 (). cdliciildtd . TIk' i::onan<i:ia aie of vei'v t-haracteristic foi-iii. They 

 rniiM-ldy iX'seinhk' a seven- oi' eight-sided prism, but the sides are- 

 curved instead of flat. The h)n<ritudiual lines are simply th^ optical' 

 expression of the folds in the perisare, where the sides meet. These 

 lines usually appear nioie or less irieuular, being bi-oken and want- 

 ing in parts, and in comparatively few cases are they fairly sti'aight 

 an<l uniform tlii-oughout. The gonotheca is subject to quite as many 

 irregularities as in the allied species; I have seen examples with a 

 deep constriction round the middle, and others with a series of" 

 irregular aniiulations. The sexes do not differ in foi-m. There are- 

 two medusae, one of which may be so lai-ge as to nearly fill the- 

 capsule, while the other is still very small. In one case I saw what 

 seemed to be otocysts. 



The absence of a distinctly compressed condition of the gonangia 

 differentiates this species from all the others referred to in this 

 paper. 



Okthopvxis platycarpa n. ><p. (Pis. XI. and XII., Fig 3). 



Hydrorhiza stout, peduncles distinctly waved, mostly 2-4 times as 

 long as the hydrothecae. 



Hydrothecae large, wide-based in the broader aspect, with the 

 walls often somewhat thickened, principally in the form of a convex 

 sub-marginal band, narrower aspect less thickened or not at all, 

 border plain, distinctly everted. Length, .o3 — .4.3 mm., width at 

 Ijorder, .32— .39 mm. 



Gonothecae large, very much compressed, smooth, Avith straight 

 sides forming angles at the summit, which is slightly lower between 

 them, a single gonophore filling the capsule when matui-e. Length., 

 alxnit 1.55 mm., width .72— .90. 



Hah.— In or near Port Phillip. 



This form, in the strongly compressed hydrotliecae, the bi-oad^ 

 basal portion, and the form of the thickening, shows most affinity 

 with O. mncrogona, and occasionally a hydrotheca is seen which 

 might readily be taken for one of that species. The gonangia, how- 

 ever, differ greatly in their straight sides and squarish summit (as 

 seen in their broader aspect), and in their much compressed form. 

 Seen edge-wise they appear slightly curved alternately in opposite- 

 directions. In each of the few specimens which I examined there- 

 was a single large gonophore, occupying the Avhole cavity, but they 

 were not in a condition to permit of their character being made out 

 satisfactorilv. 



