152 Rev. T. Hincks on Deejj-ioater 



of this species which he had obtained from Greenland and 

 Massachusetts; it may very probably be identical with the 

 Icelandic form. Packard also tells us that in the Straits of 

 Belle Isle (Labrador), 8. jiolyzonias is found " very stout and 

 large " in the deeper water. 



Sertularella geniculata^ n. sp, PI. VII. figs. 13, 14. 



Stevis slender, decidedly geniculate, simple or slightly 

 branched, jointed and twisted above each calycle ; the 

 internodes long, attenuated below, and bent in opposite direc- 

 tions. Hydrothecce very distant, ribbed transversely, chiefly 

 on the upper half, rather broad below, and narrowing gradually 

 towards the aperture, which bears four very prominent teeth, 

 is sinuated deeply between them, and is surmounted by a 

 conical quadi'ipartite operculum. Gonothecm unknown. 



Height (of the largest specimen met with) about 4- inch. 



This is a critical species. In general character it closely 

 resembles S. tenelJa, Alder ; but, after careful examination, I 

 feel little doubt that it is a distinct form. The stem is zig- 

 zagged ; the internodes, which bend in opposite directions, 

 are so much attenuated below as to have the appearance of 

 distinct pieces jointed together rather than of the segments of 

 a continuous stem. They are longer than those of 8. tenella, 

 and rather less decidedly twisted or annulated at the base. 

 The calycles are about half as large again as those of the 

 allied species ; they want the regular barrel-shape of the latter, 

 are not rounded off below, but broad and squarish, and do not 

 taper off so decidedly towards the upper extremity. They 

 want altogether the constriction immediately below the 

 aperture, which, to a greater or less extent, is found in 8. 

 tenella. The teeth are very large, prominent, and acuminate, 

 and the margin is deeply sinuated between them ; while 

 in the last-named species they are comparatively incon- 

 spicuous, and the rim is very slightly depressed between them. 

 The aperture is " conspicuously squared " m. 8. tenella, and 

 the operculum rises hut little above it • in 8. geniculata the 

 operculum is prominently conical. The transverse ribs are 

 much less pronounced, not giving the sharply crenulated 

 appearance to the sides which they do in 8. tenella ; and they 

 extend generally over a smaller proportion of the calycle. The 

 contour and " set " of the hydrothecte are very different in the 

 two forms, though it is very difficult to give an exact idea of the 

 difference in a description. The sides are rounded or curved 

 outwards in 8. tenella, almost straight in 8. geniculata. 



To sum up, the former species has neat, rounded, barrel- 



