125 



frontal edge of the ocecia is almost at the same height as the basal ; 

 the avicularia smaller than the zooecia: 



5) The lateral walls within the covering membrane generally with 

 numerous spine-like processes; the margins of the zooecium have as a" 

 rule more or fewer (occasionally numerous) spines; the avicularia 

 generally with a pointed mandible; the ocecia not rarely immersed in 



the avicularia Spiralaria Busk. 



(Hincksina Norm.) 



5) The lateral walls never have spine-like processes, at most a single 

 pair of spines: the mandible of the avicularia rounded, ocecia never 

 immersed in avicularia Heteroflustra nov. nom. 



Spiralaria Busk, char, emend. 



? Hincksina Norman ^ 



(PI. I, fig. 9 a). 



The lateral walls with as a rule a row of spine-like processes (or denticles) 

 a short distance within the covering membrane; the edges of the aperture as a 

 rule furnished with spines, sometimes over their whole length; the avicularia 

 generally with beak-shaped, pointed mandible; the ocecia most often immersed in 

 avicularia; the side- walls have numerous uniporous rosette-plates. 



As will be seen from the above diagnosis, the characters on which the genus 

 is based are not constant; but as these characters in the species which I refer 

 to this genus supplement one another in such a waj', that there can be little 

 doubt that these species are closely connected, I must consider this genus as 

 well-established, though its limits are not sharp. Besides in the species, which 

 Busk originally described as Spiralaria florea^, the above-mentioned, spine-like 

 processes on the side-walls are also found in Fl. dentigera^, Fl. spinuligera^, Fl. 

 denticulata^, to the last of which Busk has referred two fairly distinct forms, 

 and it seems on the whole to be subject to considerable variation. I may men- 

 tion here the most important characters for the three forms in our Zoological 

 Museum, which can be referred to S. denticulata. 



A form from the Challenger St. 163 (var. inermis). There are no spine-like 

 processes in a larger or smaller distal portion of the zooeciiim, whilst in the 

 proximal portion 1 — 11 appear on each side; no spines; typical avicularia, no 

 ocecia. 



A form from Bass' Straits. Strong, spine-like processes in almost the whole 



' 83, p. 585, « 6, p. 153. '' 109. 



