34 O. NORDGAARD. [2nd ARC. EXP. fram 



Rh. hincksi. 

 c. Frontal wall perforated; ooecium with small depressions, but 

 no pores: 



Rh. ovata. 

 B. With distinct median denticle. 



a. Large zocEcia with strongly-marked ribs : 



Rh. costata. 



b. Large zocecia with smooth frontal wall and distinct puncturing 

 on the basal wall : 



Rh. plicata. 



c. The zooecia with marginal pores and reticulated ornamentation of 

 the frontal wall, and 4 oral spines: 



Rh. spinigera. 



d. The zooecia crowded together; frontal wall generally without 

 ornament. Peristome folded outwards : 



Rh. bilaminata. 



e. The zooecia crowded together; the peristome drawn up over the 

 ooecium, and the frontal wall furnished with ribs and depressions : 



Rh. radiatula. 



In addition to the above there also occurred among the specimens 

 from the 2nd Fram Expedition, the following: 



65. Rhamphostomella, contigua, Smitt. 



1867. Cellepora ramulosa f. contigua Smitt, Ofv. Kgl. Vet. Akad. Forh., 1867 



(Appendix), pp. 31 & 189, pi. 28, figs. 193-201. 

 1905. Bhamphostomella contigua, Nokdgaard, Hydr. Biol. Inv. Norw. Fj., p. 172, 

 pi. 5, figs. 18-20. 



July 22, 1900, the neighbourhood of the winter haven; 1900, the 

 north side of N. Devon, incrusting stones; July 13, 1901, a little north 

 of Cape Land's End, incrustation on stones. 



According to the form of the operculum, this species cannot well 

 be regarded as a Cellepora, and in my above-named work I referred 

 the species to Rhamphostomella, because I knew of no better place to 

 put it in ; but it can hardly be regarded as a typical form of this genus. 

 In higly calcified colonies from the neighbourhood of the winter 

 haven (July 22, 1900), little or nothing of the spines on the oral margin 

 were visible. 



