1898-1902. No. 8.] BRYOZOA. 



33 



The best drawing of the species is to be found in Lorenz's „Bi7ozoen 

 von Jan Mayn." 



64. Rlmmphostomella bilaminata, Hincks. 

 PI. IV, fig. 57. 



Syn. BiDENKAP Fort., p. 32. 

 Also 



1905. Bhawiphostontella pUcata, Nordgaard, Hydr. Biol, Inv. Norvv. Fj p 171 

 pi. 5, figs. 14 &• 15. 



Septennber 19. 1900, off Forvisnings Valley, 2-20 fath.; July 12, 

 1901, bay at Land's End. 



The peristome is folded a little outwards. The avicularium, which 

 is borne on a lateral prominence, is considerably smaller than in plicata. 

 The length of the mandible is only a little greater than its width. 

 Occasionally a few ribs are found upon the frontal wall of the zooecia. 

 I presume that on Smitt's Plate 28^ figs 189 & 190 represent Rh. pli- 

 cata, while fig. 191 is bilaminata. The length of the zooecia varies 

 greatly (from 0.5 to 0.9 mm.), the width being from 0.4 to 0.5 mm. 

 The frontal wall had as a rule no special ornament, but the basal wall 

 had a strongly-marked puncturing, although this character appears to be 

 very variable. The median denticle on the lower oral margin is very 

 marked, and there are indications of a little short denticle on each side 

 of it. As a rule there are few pores in the ooecia, but there is great 

 variation in the number of pores. 



The only representatives hitherto known of the genus Rhampho- 

 stomella are from northern cold waters. Neither Waters^ nor Gal vet* 

 give any species of the genus from southern cold seas. 



Among the specimens from the 2nd Fram Expedition, all the 

 species of the genus known at present occurred, except Rh. fortissima, 

 Bidenkap*. 



In order to facilitate the determination of these species, the follow- 

 ing little table is given: 



A. Without median denticle. 



a. With large, ribbed zooecia: 



Rh. scabra. 



h. Frontal wall entire and quite even: 



1 Ofv. Kgl. Vet. Akad. F8rh., 1867. 



2 Bryozoa. Voyage du S.Y. „Belgica". Antwerp, 1904. 



3 Bryozoen. Hamburger Magalhaensische Sammelreise, Hamburg, 1904. 

 * Die Bryozoen. Fauna Arctica (ROmer & Schaudinn edit.), 1900. 



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