MICROPORELLA MALUSII. 213 



Lepralia thyreophora, Busk, is a very unimportant varia- 

 tion upon the normal M. Malusli. The inclosed " scuti- 

 form area/' which is its principal feature, is due to a very 

 slight change in the ordinary constitution of the cell. The 

 raised line which bounds its anterior surface, and which 

 is generally so far down as to be all but invisible, in the 

 New-Zealand form is placed higher up on the front of 

 the cell, where it is distinctly seen, inclosing a smooth 

 area, and edged along its inner margin by a line of the 

 stellate pores. The size of the area, however, varies greatly; 

 and there is a marked tendency to a return to the normal 

 condition. I have noticed that in this variety the cells 

 are much less closely compacted together than in our 

 British form ; and to this in great measure, I think, is due 

 the peculiarity just referred to. Apart from these points, 

 the New-Zealand species agrees entirely with our own. 



HABITAT. On weed, shells, stones, &c., from inshore to 

 deep water (60 fathoms) . 



LOCALITIES. Widely distributed and abundant. Guern- 

 sey ; South Devon ; Cornwall, 60 fathoms ; Isle of Man 

 (T. H.) : Sidmouth, a transparent variety on weed (Mrs. 

 Gatty) : Killinchy, co. Down ; Roundstone (W. T.) : 

 coast of Antrim, deep water (Hyndman) : Northumber- 

 land, occasionally (Alder) : St. Andrews (Dr. M'Intosh) : 

 Wick (C. W. P.) : Ayrshire (Landsborough) : the Minch ; 

 Shetland, tide-marks to 50 fathoms (A. M. N.) : Birter- 

 buy Bay (G. S. Brady) : &c. 



GEOGRAPHICAL DISTRIBUTION. Gullmaren, Bahusia, 

 10-20 fathoms (Smitt) : Bergen (A. M. N.) : Finmark, rare 

 (Loven) : Greenland (Liitken) : Mediterranean (Manzoni) : 

 Adriatic (Heller) : France, south-west (Fischer) : Black 

 Sea (Ulianin) : South Patagonia, 48 fathoms ; Terra del 

 Fuego ; Falkland Islands (Darwin) : Valparaiso, on shells 

 of Venus thaca, very common (D'Orbigny) : New Zealand 



