Mr. T. Whitelegge on Australian Polyzoa. 19 



four or five cells near the base ; oral aperture immersed, 

 rounded above, and a sinus below which is about ^ the diam- 

 eter of the mouth ; operculum ovate, constricted (?) near the 

 base, with two circular spots on the upper half; peristome 

 elevated on each side, depressed below the mouth ; orifice 

 ovate, with a pore on the upper margin ; avicularia forming 

 elevated rows between the zooecial orifices ; mandibles trian- 

 gular, with an acute point ; under surface of zoarium when 

 perfect covered with a calcareous lamina, with a number of 

 avicularia, some on elevations and others in circular depres- 

 sions; on the summit of the zoarium there is usually a 

 cluster of irregular avicularia bearing cells with long acute 

 mandibles. 



Loc. Holborn Island, Port Stephens, and Bass's Straits. 



The question of priority in this species is, I think, in Mr. 

 Woods's favour. His paper was read in September 1879, and 

 would probably be published early in 1880. Mr. Haswell's 

 was read in January 1880, and would probably be issued in 

 April or March, while that of Mr. Hincks did not appear 

 until August 1881. 



The figures of the zooecia given by Mr. Has well and those 

 also of Mr. Hincks are, I think, upside down, judging from 

 the shading and the very 'narrow sinus shown, but which is 

 really more like the pore above the mouth than the true oral 

 sinus ; the latter is in perfect specimens about ^ the diameter 

 of the mouth. The zooecial apertures in Mr. Woods's figure 

 are badly drawn ; still it is the right side up, and shows a 

 correct view of a " semilunar slit with the concavity directed 

 outwards " and an aviculariura below pointing downwards. 

 It will be also interesting to note that it is on the elevated 

 ridge which carries the avicularia ; and, further, it shows the 

 intercalary method of growth as well as the formation of an 

 incomplete row of zooecia. Altogether this figure gives the 

 general features of what really takes place in the species. 



The slit which indicates the formation of a new cell in- 

 variably has an avicularium below, with the mandible 

 pointing downward at first ; but as growth goes on this is 

 usually forced to one side of the mouth, though occasionally 

 it remains in front. 



6. Bipora umhonata (Haswell). 



Eschara umbonata, Haswell, op. cit. p. 41, pi. ii. figs. 5, 6. 



Zoarium free, bilaminate, flat, simple or forming trilobate 

 expansions j " surface ornamented with numerous rounded 



2* - 



