SABELLIDES AND SERPULIDES 



247 



NOTES ON SOME PREVIOUSLY DESCRIBED SPECIES 

 OF SPIRORBIS, WITH DESCRIPTIONS OF NEW 

 FORMS FROM THE ATLANTIC. 



Spirorbis granulatus Linne 1767. p1. xl, fig. 24; p1. xliii, fig. 32. 



This small species is well figured by Levinsen (1883, p1. hi, fig. 9 ; 

 fig. 10 is a different species). It is very common on bryozoans ( Cel- 

 leporaria^ Escharopsis^ Porella^ etc.) from the Grand Banks of 

 Newfoundland, Gulf of St. Lawrence, and Greenland; though often 

 larger and less regularly coiled it is readily distinguished by the three 

 conspicuous thin lamella-like carinas. The name, however, has been 

 erroneously applied to several other forms, as the following : S, 

 granulatus Fabricius 1780= violaceus Levinsen 1883; granulatus 

 Montagu iSo^^ = S7il cat us Adams 1797; granulatus Langerhans 

 1880, and probably also that of Saint -Joseph \Z<^^ — militaris Cla- 

 parede 1868 ; granulatus Caullery and Mesnil 1897 = ? ; granulatus 

 Moore 1902 = triangular form of quadrangular is Stimpson 1853. 



Spirorbis verruca Fabricius 1822, non Levinsen 1883. p1. xli, figs. 3, 

 12; p1. xliv, figs. I, 16. 



Numerous specimens of a good-sized, thick, opaque, white, sinistral 

 tube with spreading base and small central cavity, attached to a valve 

 of Chlamys islandicus from Greenland, are identified as S. verruca^ 

 as they seem to agree more closely with Fabricius' description than the 

 larger form figured by Levinsen (1883). The surface is ornamented 

 with one, sometimes two, small rounded spiral threads, rarely suffi- 

 ciently prominent to be termed carinas. In adults, at the upper angle 

 of the inner or columellar margin, the edge of the aperture is tilted 

 upward ; sometimes the ends of the threads form obscure projections 

 on the upper edge. 



The calcareous plate on the operculum, which becomes a brood- 

 pouch, can scarcely be distinguished from that of S. validus Verrill, 

 but the collar setae differ in being less numerous and in some having an 

 obscure posterior notch. 



Specimens on Nothria tubes from Greenland, identified by Moore 

 1902, on examination prove to be the discoid form of S. validus V. 



Spirorbis vitreus Fabricius 1780. p1. xli, fig. 14; pi. xlii, figs. 6, 7. 



Some immature forms of this dextral hyaline species have a rounded 

 thread or cingulum on the top of the whorls, ending at the aperture in 

 a tooth-like projection. 



