Natural Hislory of East FinmarJc. 589 



C. unicornis pore-chambers are rarely developed, but some- 

 times one or two may be so. 



I have examined the pore-chambers in the follov.'ing 

 species, which I would include in the genus. Two pairs of 

 lateral and one distal pore-chambers are present in lineafa, 

 craticuin, Whiteavesii, Bumerilii, aurita ; two pairs of lateral 

 and ? one distal (the latter not being clearly seen) occur in 

 Sophia. Levinsen has placed unicornis among the species 

 which have no pore-chambers ; that is true as a rule, but 

 rarely there is one chamber or one pair of lateral chambers, 

 and rarely two pairs, and this applies also to var. arniifera, 

 Hincks. I have not been able to see the pore-chambex's in 

 nigrans, as it is usually loosely attached and the back is too 

 solid and dark to enable the pore-chambers to be seen. Of 

 curvirostris and arctica (Smitt) my specimens are too small 

 to allow of sacrificing them ; and discreta, Hincks, is un- 

 known to me. In craticula and Whiteavesii the membranous 

 area occupies only the central portion of the front wall, and 

 outside the spines which surround it there is a calcareous 

 crust of some breadth which completes the front wall. 



34. Callopora lineata (Linne). (PI. XIII. fig. 2.) 



Vadso, on seaweeds ; stones and shells of Buccinum groen- 

 lundicum, var. nuda ; at Vardo on Neptunea despecta ; also 

 Svolvaer and in Bergen and Hardanger Fiords. The East 

 Finmark specimens which I have seen are remarkable from 

 the absence of both ooecia and avicularia. Spitsbergen with 

 ooecia and avicularia (from Smitt). 



35. Callopora craticula (Alder). (PI. XIII. fig. 3.) 

 Varanger Fiord in 100-125 fathoms ; and I may add 



"Finmark" {Smitt, as " M. lineata "), West Greenland, 

 'Valorous,' Gulf of St. Lawrence {Whiteaves). 



The figure of Hincks is not quite satisfactory : it does 

 not illustrate how close the flattened glistening spines are 

 to each other at their edges ; nor does he show any avicu- 

 larium at the top of the ooecium, which is its usual position. 

 The spines in this species ordinarily almost meet and even 

 cross in the centre, thus forming a kind of roof over the 

 zooecium ; and if the tips of the spines coalesced we should 

 have a Memhraniporella, but in this case they do not show 

 the slightest tendency to form union. 



Callopora Whiteavesii, sp.n. (PI. XIII. fig. 9.) 



1867. Menibranipora lineata, Smitt (partiin), " Kritisk Forteckniug, 



&c." pi. XX. fig. 26. 

 Zooecia small, 0*5 millim., oval, each area with it's own 



