THE MAEINB FAUNA OP THE FALKLAND ISLANDS. 71 



VIII. Porella tridentata, sp. nov. On shell {Euthria antarctica) 



Falklands. 

 Of the foregoing list of species, the following have not, I think, 

 been hitherto recorded from the Falklands : — 



1. Cellepora pustidata. 



2. Lepralia adpressa. 



3. Membranip>ora membranacea. 



4. Smittia landsborovii. 



5. Micropora uncifera. 



6. Microporella ciliata. The variety personata was recorded by 



Darwin from the Falklands, but not the true species. 

 Of 16 species of Bryozoa in this collection, eight have been found 

 only in the southern hemisphere. Five have been found in the north 

 and south temperate regions. One occurs in the north and south tem- 

 perate regions and in the tropics, and two are cosmopolitan. 



Notes on the Species of Bryozoa in this collection. 



The zooecia of Microporella ciliata seem larger than those of the 

 British specimens. In structure I think they more closely resemble 

 those of the Californian specimens. 



Lepralia adpressa var. Busk. The surface of the zooecium is 

 strongly grooved, as described by Busk of the species occurring at 

 Chiloe {see Busk, Brit. Mus. Cat., Vol. II., p. 82) but there are, in 

 addition, certain large pores which occur round the margin of each 

 zooecium at the base of each triangular furrow {see Figs. 1 and 2). 

 These pores I have also seen in Busk's " Chiloe " specimen at the 

 British Museum, but they are neither so numerous nor so well marked 

 as in my specimen. 



Avicularia (Fig. 3) of two kinds occur, which have not hitherto been 

 described ; one appears to be the ordinary beak -like form, but is often 

 slightly irregular in shape (Fig. 3, a and b) ; the other is circular in 

 outline, with a spatulate mandible (Fig. 3, c and d). The avicularia 

 are very irregularly distributed over a colony ; sometimes five or sis 

 neighbouring zooecia possess one or even two, whilst not one of the 

 remaining zooecia of the colony bear any. 



In one or two cases, knobbed cells are seen (Fig. 1, a), which are 

 characteristic of the British species {see Hincks, Brit. Mar. Polyzoa, 

 p. 307). I have seen no trace of an ovicell. 



