14 Mr. T. Wliitelegge on Australian Polyzoa. 



but he omits to mention details in his description. Mr. 

 Waters (Quart. Journ. Geol. Soc. 1882) gives figures of 

 Lunulites cancellata in which the oral aperture is shown, but 

 these are also the wrong side up, and in his description he 

 simply refers to it as a secondary orifice with a proximal 

 sinus. It is in my opinion clear that he did not at the time 

 recognize the true significance of this " secondary orifice." 

 Another prominent feature which is figured by Mr. Woods 

 and well described by Mr. Haswell as " a narrow semilunar 

 slit with the concavity directed outwards " has in most cases 

 been overlooked and its true import hitherto unnoticed. 



The facts as to the actual structure of the species already 

 mentioned have been derived from an attentive study of 

 specimens in the collection of the Australian Museum, Mr. 

 Woods's types in the Macleay Museum, and some lent to me 

 by Mr. J. Brazier. 



The structural features presented by the various species of 

 this group are of such an exceptional character that it will be 

 necessary to remove them altogether from the family Selena- 

 riadge, in which most of the species have been placed. In 

 fact they appear to possess characters which are either 

 unknown or rarely found in other species of Polyzoa ; and 

 possibly when they have been fully investigated they may 

 form the nucleus of a new family. 



The method of growth (not habit or form) or increase in 

 size of the zoarium by the addition of new zocecia is interca- 

 lary, taking place on the surface between cells already formed, 

 and not at the outer margin, as in most other known Polyzoa. 

 The only instances of intercalary growth, so far as I have 

 been able to ascertain, are recorded by Mr. Hincks ; but in 

 these cases it is confined to the ovicelligerous cells of Schi'zo- 

 porella hyalina and S. linearis. 



The formation of new zocecia does not appear to be con- 

 fined to any particular part, but may take place at any point 

 between the centre and the margin ; when near the latter the 

 zooecium is formed in the space intervening between two, and 

 when nearest to the former in the intervening space bounded 

 by four zocecia. The direction of the zocecia is also appa- 

 rently reversed, from the fact that the free distal edge of the 

 operculum is nearest to and directed towards the apex in 

 those of a conical form, and to the apparent base in those 

 which are flattened, while the hinged or proximal end is 

 nearest to the outer margin of the zoarium. 



The manner in which the peristomial orifice is formed 

 appears to be just the opposite to what obtains in other peri- 

 stomiate Polyzoa, and there is a special feature of an important 



