148 MEMBRANIPORID^. 



Shetland^ shallow water, Hillswick ; on Laminaria, Bres- 

 say Sound (A. M. N.) : Wick and Peterhead; Cornwall 

 (C. W. P.). 



Geographical Distribution. Davis Strait, 100 fms. 

 (Wallich) : Gulf of St. Lawrence (Dawson) : Bahusia, 

 7-10 fms. (Smitt) : Spitzbergen, on CellularicB, hydroids, 

 &c., 20-45 fms. (Swedish Exped.) : Nova Zembla, 4- 

 60 fms. ; Kara Sea (Nordenskiold) . 



Range in Time. Scotch Glacial deposits (Geikie) . 



This is an exceedingly pretty species, recognizable at a 

 glance by its general aspect, even without a minute exami- 

 nation of the characters. The cage-like appearance of the 

 little cells, with their closely-set glittering bars, their 

 small size, and the extreme regularity of the linear series 

 in which they are disposed, are points which at once arrest 

 attention. 



The spines are crowded together at the lower part of 

 the cell, over which they bend, and converge to a central 

 point. The two immediately below those which stand erect 

 are larger than their companions ; and their free extremi- 

 ties curve upwards. It should be noted that there is an 

 essential difference between the erect spines and those 

 which bend inwards and protect the area of the cell. The 

 latter only exhibit the flatfish glistening appearance so 

 characteristic of the species ; the others are rounded and 

 of the usual type. 



M. craticula, so far as our present knowledge goes, 

 must be accounted a rare species. 



