Natural IJhtoru of East Finmarh. 93 



to thoroughly understand the v/kj in which C. nitido-punctata 

 assumed its unusual form, and this led on to the examination 

 of the enUre family. 



Nitida (PL VIII. fig. 8). — Three bars are here represented. 

 It will be observed that they are of irregular form, the exact 

 character of which is decided by the necessity of forming 

 distal junction with their collateral and opposite neighbours : 

 the line of junction in this particular species has a waved 

 zigzag cliaractcr. The bar at its commencement in the side 

 wall is a rounded loop. This is the first point of great 

 importance to note because the existence of such a loop in the 

 side or front wall of all Crihrilina leads us to understand the 

 building up of the zoojcium in some obscure cases. The 

 second point of primary importance is the presence of a very 

 large lumen, which here occupies the whole of the interior 

 of the bar. In some forms we find that this lumen is only 

 indicated by a fine central line, or by the presence in that 

 line of a minute pore ; or all trace of it may be obliterated 

 by the overgrowth of a rib, which is raised over the lumen- 

 line. 



Melolontha (PI. VIII. fig. 9). — The character of the bars is 

 similar to tl)at of nitida. In the first bar which is drawn 

 there will be noticed a tendency of the lumen to divide and 

 form a fork. In other species it will be found that this is 

 carried further. 



Annulata (PI. VIII. fig. 10). — The figure given is drawn 

 from an unusually simple form of the species * living on a 

 frond of Lumiiiaria, but has some special chai^acteristics. 

 The bars are only loosely attached and not cemented together; 

 and on boiling in liquor potassse the zooecium in many cases 

 broke up, the bars separating. The lacunes between the bars 

 in the zooecium illustrated are the result of the simple 

 contact of two bars here and there, and each bar retains its 

 own strongly marked margin ; and thus we have the earliest 

 and simplest mode of formation of these lacunes, in the producing 

 of which two bars always take part. The bars themselves, 

 M'liich in this specimen are more flattened than usual, have 

 the appearance, at first sight, from tlieir opacity and brownish 

 colour, of being solid; but closer inspection reveals a pellucid 

 circle in the loop of the bar within the marginal line of the 

 zooecium which indicates the end of the lumen, while at the 

 distal end of many of the bars there is a small pore, and the 

 conviction becomes almost a certainty that a lumen fills the 

 whole bar except the narrow marginal line. The ordinary 



* Kindly g'iveu me by Dr. Harmer ; lie procured it at Godcisand, olF 

 Tysnasi) in JjjiJrne Fiord, Norway. 



