Pvlyzoa of the Adriatic. 257 



Synnotuni avicu^are, Pieper. 



Gemellaria avicularis, Pieper, loc. cit. 



Notamia amcularis, Waters, " Supplemeutal List of Polyzoa from Bay 

 of Naples," Jouru. Roy. Alicroscop. Soc. ser. 2, vol. v. (1885). 



Zoarium minute, slender, of delicate texture, glossy, simple 

 in habit, consisting of long stems, which bifurcate at rather 

 distant intervals. Zowcia in pairs, back to back, elongate, 

 expanding gradually upwards from the base, whicli is much 

 attenuated and tube-like, somewhat prominent above ; the 

 aperture occupying more than two thirds of the front, nar- 

 rowing to a point below, the margin thin and unarmed ; lateral 

 avicularia small, sessile, placed at the top of a cell, on the 

 inner side, adnate, developed alternately on the right and left 

 of the zoarium, widening from the base upward, with a minute 

 beak ; median avicularia articulated, capitate, placed at the 

 top of each pair of cells on the central line, subglobular, 

 smooth, the beak very slightly produced, with a sharp spike- 

 like extremity. 



Hah. On the underside of stones, NuUipore, &c. 



Range. Adriatic (Pie/>er) ; Bay of Naples {Waters). 



In the present form the shoots originate in a pair of rudi- 

 mentary zooecia, which are much shorter than the mature cells 

 and are not prolonged below the aperture. They are desti- 

 tute of avicularia, but give off from their lower extremity a 

 number of long tubular fibres. From these primary zooecia a 

 normal pair is developed, which immediately bifurcates, giving 

 origin to two separate lines of cells. In the fork between the 

 two branches is placed a capitate avicularium. After au 

 interval bifurcation takes place again, but it is not carried 

 further in any specimen which 1 have examined. Above 

 each bifurcation there is only a single zooecium, as in Notamia^ 

 instead of the usual pair. Generally the course of development 

 is the same in Synnotum as in Notamia bursaria ; but in the 

 latter the primary cells are borne on a stem which rises from 

 a " rather stout creeping tube." 



There seems to be little difference in general structure 

 between the sessile and capitate avicularia, though they are 

 very dissimilar in size and appearance. They agree in 

 minute details and little change is needed to convert the one 

 into the other. The stemmed avicularium of Notamia, and 

 especially the larger form of it which occasionally occurs, 

 marks a distinct advance towards the articulated form, and is 

 intermediate between the two appendages of Synnotum. 



A remarkable feature of the present species is the number 

 of very long tubular fibres which are given off from all regions 



