Alcyonuria . G 23 



remains exsert. This may happen to the entire colony, or part of the polyps 

 may be in this state and part may be entirely retracted, depending upon the 

 intensity of the contraction. Thus the general appearance varies considerably. 

 The mode of branching in the larger specimens is arborescent but quite variable 

 and irregular. 



The walls of the main stalk and larger branches, when not greatly con- 

 tracted show, under the microscope, the small, short, often somewhat stellate 

 spicules scattered and well separated. On the stems of the smaller branches 

 the spicules are usually more numerous, and some are larger, often interlocking, 

 but in some places well separated. The calicles are not at all prominent, usually 

 immersed, and surrounded or separated by a small amount of coenenchj^ma. 

 The spicules of the branches vary much in size in different specimens, according 

 to the locality of origm. 



In general, the spicules are mostly about three-fourths the size of the 

 corresponding forms in G. rubiformis, but sometimes are nearly as large. The 

 figures of the spicules on PI. IV, are much more enlarged than those of the 

 latter, or those of G. canadensis. 



This species is common on stony or shellj^ bottoms from the southern part 

 of the gulf of St. Lawrence to the moderately deep waters near Block island 

 and Watch hill, R.I., and off Stonington, Conn. It is most common in 10 to 

 30 fathoms but occurs down to 55 fathoms. I have taken it at low water of 

 extremely low tides at Eastport, Maine. It was found by us particularly large 

 and abundant south of Cape Breton, N.S., and off Cape Cod in 15 to 20 fathoms. 

 At the latter place it was associated with great numbers of Gorgonocephahts 

 (or Astrophyton) agassizii, which were clinging tenaciously to the Alcyonariaos 

 by their tendril-like arm-branches. It does not appear to extend to the sul)- 

 arctic coasts nor to any great depths. 



Variety or Sub-species, G. carnea niicrostella V., Plate IV; fig. 3. 



The specimens coming from south of Cape Cod to the eastern part of Long 

 Island sound differ from the more northern ones in having the spicules of the 

 cortex of the stalk and branches much smaller and farther apart. They are 

 also more stellate in form. The modes of branching, form, and colours, are 

 the same as in the trypical form (see PI. IV, fig. 3, a-m). 



Gersemia fruticosa (M. Sars) Molander. 



Alcyonium fruticosum M. Sars, Forh. Vid. Selsk. Christiana, 1860, p. 140. 



KoREN and Danielssen, Fauna Litt. Norvegia;, Vol. iii, p. 81, pi. Ill, fig. 



8-II, 1877. 

 Gersemia florida Marenzeller, Akad. Wiss. Wien, Vol. 35, p. 375, pi. Ill, figs. 



2-3, 1878, (non Rathke, t. Jungersen.) 

 Gersemia danielsseni Marenzeller, Die Inter. Polarf., 1882-1883 (t. Jungersen). 

 Vceringia fruticosa + V. arborea Jungersen, Kara Havets Alcyonider, 



Dijmphna Togtets, Zool. Bot. Udbytte, pp. 375-378, pi. 32, figs. 1-13; 



pi. 33, figs. 1-12, 1887. 

 V. mirabilis+fruticosa+abyssicola + polaris+pygma;a+dryopsis+JanMayeni + 



clavata + capitata+Barathrobius digitatus + B. palmatus+Krystalophanes pol- 



aris+FuUa schierzHi + Nannode7idron elegans + Nidalia arcUca + Orgamdus 



nordenskioldii + Sarakka crassa, etc. (t. Jungersen), Danielssen, N. 



Nordhavs Exped., Alcyonida, 1887, pi. 1, 2, 7, 8-10, 15, 16-21, 22, 23, m 



part. 



