284 On Marine Polyzoa. 



ai)pendages. In an account of some Polyzoa from the coast 

 of Burmali (' Annals' for May 1880) I have noticed a form 

 under the name of var. hhnucronata^ which is distinguished 

 by the lateral elevation of the peristome into mucronate pro- 

 cesses, and is also furnished with a very large pointed avicu- 

 larium, placed on a mound-like rising beside the orifice. 



This bimucronate variety also occurs off the coasts of Vic- 

 toria. Another from the same region (PI. IX. %. 4) is 

 also furnished with a mounted lateral appendage, sometimes of 

 moderate, sometimes of gigantic dimensions ; but in this case 

 the form is spatulate. Close to the orifice at the side there is 

 also very frequently a small pointed avicularium, with the 

 mandible slanting upwards. In addition there is on many 

 of the cells a minute spatulate appendage unmounted on one 

 side of the mouth. 



This seems to be the variety siKithulata of Smitt, figured 

 in his ' Floridan Bryozoa.' 



Yet another form {mwiita) occurs off Port Phillip Heads, in 

 which, on a great proportion of the cells, there is a large rising 

 on one side of the orifice, on which is placed an avicularium 

 with either a broad pointed, or spatulate mandible, or one 

 attenuated and slender towards the extremity, directed down- 

 ward. A sessile, slender, subspatulate appendage is also 

 present on many of the zooecia. This is a very marked form. 



As it occurs in the British seas S. trispinosa has usually 

 two modifications of the avicularium — one with a large tri- 

 angular mandible, very variously placed, the other small and 

 oval in shape, placed laterally. 



These variations are interesting morphologically, and espe- 

 cially so in relation to the wide geographical distribution 

 which this species enjoys. 



EXPLANATION OF THE PLATES. 

 Plate VIIL 



Fif/.l. Scliizo^wrella iiuhsinuata,-a.. s^. la. Avicularium. 



Fig. '2. Farciminaria uncinata, n. sp. 2 «. Nat. size. 2h. Ooecium, 



viewed sideways. 2 c. The same, front view. 

 Fi(j. 3. Lcpralia hlfrons, n. sp. 3 a. Zoreclum with ovicell and avicu- 



Lirium. 3 b. Orifice of cell without the operculum, showing the 



large lateral denticles. 3 c. Orifice, with the operculum in situ. 

 Fig, 4. Memhranipnra jwrfragilis, MacGillivray (sp.). A group of cells 



with the avicularium. 

 Fig. 5. Cribrilina monocerus, MacGillivray. Young cells. 



Plate IX. 



Fig. 1. 3Ienipea marginata, n. sp. la. Portion of the stem and branches, 

 magnified, to show the stout habit. 1 b. Part of the margin 

 of the branch, viewed in protile. 1 c. One of the large avicii- 



