ATLANT. DEEP-SEA EXPED. 1910. VOL. 



PENNATULACEA. 



fore quote them here: — "When taken from the trawl the 

 polyps and membrane covering the hard axis of the stem 1 ) 

 were so brightly phosphorescent, that Captain Maclear 

 found it easy to determine the character of the light by 

 the spectroscope. It gave a very restricted spectrum, 

 sharply included between the lines b and D." 



In pi., fig. 1, the artist on board the "Michael Sars" 

 has tried to give us an idea of the fascinating sight 

 afforded by the colony taken at Stat. 47, which although 

 drawn up from the immense depth of more than 5000 

 metres, was still brilliantly phosphorescent. 



Niedermeyer 2 ) has examined the phosphorescence of 

 Pteroeides griseum (Bohadsch), and states that the phos- 

 phorescence is limited to darkness, the colony losing its 

 capacity of producing light on being exposed to broad 

 daylight or sunshine, regaining its luminary power on 

 being removed from the light for some hours. These facts 

 make it probable that the phosphorescence is due to 

 chemicals, which are destroyed in daylight. 3 ) As to the 

 production of light, I cannot but agree with Niedermeyer, 

 who believes that the phosphorescence is due to intra- 

 cellular secretion. He states that the phosphorescence of 

 Pteroeides is only to be seen after the application of 

 external stimula, but I am more inclined to think that 

 deep-sea animals may produce light without any external 

 irritation. 



Fig. 4. Map showing the distribution of the "Michael Sars" Pennatulacea. 

 -4- Veretitlum cynomorium (i "Michael Sars" locality). 

 O Umbellula Giintheri (© "Michael Sars" locality. ? Doubtful 



locality.) 

 □ gracilis (FT. "Michael Sars" locality). 



A Pennatula aculeata (/\ ''Michael Sars" locality). 



The material brought home by the "Michael Sars" 

 contains only five species of Pennatulida, one of which 

 could not be identified with absolute certainty. Of the 

 four others Veretilliim cynomorium is a tropical and sub- 

 tropical species generally found in the littoral area from 

 the Bay of Biscay in the North, to Walfish Bay (South- 

 west Africa) in the South, including the Mediterranean. 

 The "Michael Sars" brought home a great many colonies 

 from Cape Bojador, in the very centre of its extensive 

 geographical range (see the accompanying map). 



Pennatula aculeata was also found within its known 

 range of distribution, both bathymetrical and geographical; 

 it had already been recorded from 140 to 2300 

 metres, and the "Michael Sars" took it in 1100 and 1797 

 metres. 



The new localities for the two species of Umbellula 

 are of greater interest, all the more because we know very 

 little about these deep-sea animals. 



Umbellula Giintheri is a typical Atlantic organism 

 previously reported from three localities. The "Challenger"*) 

 took it near the equator (Lat. 1° 47' N, Long. 26° 46' W), 

 and Verrill 5 ) tells us that it has been found at two localities 

 near the eastern coast of North-America. According to 

 Studer 6 ) Umbellula Giintheri occurs in the Pacific near 

 Central-America (Lat. 4° 56' N, Long. 80° 52' 30" E), 

 but this needs further confirmation. The "Michael Sars" 

 obtained this species at two stations to the west of the 

 Canaries, the area of distribution being thus considerably 

 extended towards the East (see the accompanying map). — 

 The bathymetrical range, too, is greatly increased, the 



') Niedermeyer's observations do not quite agree with this remark; he found that the phosphorescense was restricted to the polyps 

 and the zooids. (Studien iiber den Bau von Pteroides griseum, Bohadsch, in: Arbeiten der Zool. Inst. Wien. Bd. XIX, 1911). 



") Niedermeyer: Op. cit., p. 59. 



3 ) Some time ago my friend, the Norwegian geologist J. Oxaal drew my attention to this interesting probability. 



') Kolliker 1. c. 1880, p. 19. 



5 ) Verrii.l, Notice of the remarkable Marine Fauna occupying the outer banks off the Southern coast of New England, No. 9 (Amer. 

 Journ. Science, Vol. 28) 1884, p. 219. 



G ) Studer, Note preliminaire sur les Alcyonaires: Report on the dredging operations by the steamer "Albatross" (Bull. Mus. Comp. 

 Zool , Vol. 25) 1894, p, 57. 



