Natural History of East Finmark. 91 
how the process of modification takes place and the various 
forms are developed. As all the species cannot, in my 
opinion, remain in the two genera to which Hincks assigned 
them, I prefer to refer to them simply by their specific 
names. 
The majority of the Cribrilinidz are furnished with pore- 
chambers, but the following are without them :—melolontha, 
no pore-chamber and only two rosette-plates on the whole 
side; nitido-punctata and figulina. Nitida has two pair of 
large lateral pore-chambers and one distal, the last some- 
times being divided into two. In annulata Levinsen has 
figured (Zool. Dan. pl. v. fig. 24) the pore-chambers as very 
irregular, one lateral pair and one or two distal, or two pair 
lateral, the former of which meet in the middle of the distal 
margin, and I have seen the same variations in British speci- 
mens ; but in the var. spitsbergensis I have not seen any pore- 
chambers in the example treated with liquor potasse, the side 
walls are narrow and possibly the underlying pore-chambers 
have been destroyed in the preparation: radiata and the form 
innominata have four pair of lateral pore-chambers and one 
(or two) distal; punctata has three pair lateral (and two 
distal ?); eryptoccium has three or four pair lateral and two 
distal ; Balzact has four pair lateral and Gattye three pair 
lateral. 
The eribriline portion of the front wall in Cribrilinide is 
built up by bars, which would seem to represent the spines 
of the so-called “Membraniporide.” The diagrams annexed 
indicate the process of development. The dar A always has 
its proximal end rounded, and this rounded end I shall call 
the Joop, C: in most cases the loop has its origin in the side 
wall, B, in the same manner as a spine; but in certain species, 
as Gaitye, Balzaci, and figulina, in which the areolated or 
cribriliform portion only occupies the central part of the front 
wall, and is separated from the side wall by a considerable 
unsculptured interval, the “loops” have their origin in the 
front wall and not in the side. The bar is hollow, and in 
