270 On the Polyzoa of the Adriatic. 



cells than normal Mediterranean and Mazatlan specimens, 

 and is much altered in appearance by the modification of the 

 mouth, but is essentially identical with the present form. 



The cells of this species are commonly covered with an 

 epidermis, which partially conceals the punctures. Two small 

 round prominences are present on the operculum just within 

 the sinus. 



Range. Bay of Naples ; Mazatlan : form labiosa, Arabian 

 sea. 



Schisoj>oreUa auriculata, Hassall. . (PI. X. figs. 8.) 



A form which has hitherto been referred to this common 

 species, and which is distinguished by its large spatulate 

 avicularia, occurs abundantly amongst the dredgings from the 

 Adriatic. The peculiar avicularium is associated with a very 

 distinctive form of orifice (PI. X. fig. 8 a). The ordinary 

 cell of S. auriculata is represented in fig. 8, PI. X., and a 

 comparison of the two will show the marked differences between 

 them. The general shape of the orifice and the character of 

 the sinus are quite dissimilar. The form spathulata seems 

 always to bear the spatulate avicularium, or an elongate oval 

 avicularium, which is the earlier stage of the former. In this 

 stage the beak has a trifoliate form (PI. X. fig. 8 &), with a 

 small central projection on the infei'ior margin. The avicu- 

 larium of the normal form is, I believe, always circular and 

 very small. It may, I think, be doubtful whether the variety 

 is not entitled to specific rank. It seems to be a southern 

 form, occurring in Britain on the south-west coasts, in the 

 Adriatic, and the Bay of Naples. The point will be left for 

 further investigation. 



EXPLANATION OF THE PLATES. 

 Plate IX. 



Fig. 1. Scrupocellaria BerthoUetii, Audouin. 



Fig. 2. Ditto. Dorsal surface. 



Fig. 3. Bugida ditrupcc, Busk. Showing tlie primary cell. 



Fig. 4.. Ditto. 



Fig. 5. Bugula spicata, n. sp. 5 a. Ovicells. 5 h. Avicularium. 



Fig. 6. Bvgula plumosa, Pallas, form aperta,n. 6 a. Side view of the 



ovicell. (3 b. Cell and ovicell, front view. 

 Fig. 7, Bugula simjylex, n. sp. 

 Fig. 8. Memhranipora operculata, n. sp. 

 Fig. 9. Cribrilina punctata, var. 

 Fig. 10. Schizoporella lineolifera, n. sp. 10 a. Orifice. 



Plate X. 



Fig. 1. Schizoporella magnijica, n. sp. 



Fig. 2. Schizoporella unicornis, Johnston, form longirostris. 2 a. Avicu- 

 larium. 



