V. '07. 22 



S.K. 504.- Lat., N., 50 42'; Long., W., 11 18'; 627-728 

 fms. ; temperature at 600 fms., 8'22 C. ; 12th Sep- 

 tember, 1907. One specimen. 



No label attached. One specimen. 



Professor Hickson (1905) mentions that a single specimen 

 of Umbellula was obtained off the west coast of Ireland. Since 

 then sixteen specimens have been added to the collection. 

 These have all proved to belong to the same species, and Pro- 

 fessor Hickson has come to the conclusion that there can be 

 little doubt that they are identical with the Umbellula ambigua 

 of Marion, which was dredged by the Travailleur in deep water 

 off the coasts of Spain and Portugal (Marion, 1906). He also 

 considers it clear that there are not sufficient grounds for 

 separating Marion's species from Umbellula encrinus, differ- 

 ing as it does only in the possession of a very large number of 

 autozooids in relation to the length of the stem, while the 

 autozooids are much smaller than those of specimens of U. 

 encrinus with about the same number of autozooids. He 

 therefore names the Irish specimens 17. encrinus (Linn.) var. 

 ambigua, Marion. Jungersen (1904, p. 79, footnote) refers 

 to U. ambigua as being possibly identical with U. Thomsoni. 

 This is erroneous. 



Marion gives the length of his specimen as 400 mm. and 

 the length of the "polyp cluster" 50 mm. The stem thus 

 measures about 350 mm. The length of the autozooids (in- 

 cluding the tentacles) is given as 40 mm. Measuring from 

 Marion's drawing this leaves the bodies of the autozooids 

 about 25 mm. in length, and the tentacles 15 mm. The num- 

 ber of the autozooids is unfortunately not mentioned, but 

 judging from the figure they are quite as numerous as in the 

 Irish specimens with stems of 340 mm. and 350 mm. in 

 length, which have 29 to 43 autozooids. Comparing these 

 Irish specimens and Marion's with specimens of U. encrinus 

 obtained by the Ingolf expedition (Jungersen, 1904) we find 

 that specimens with 40, 25, 41 autozooids had stems 2,350, 

 1,090, 1,410 mm. in length respectively, and with specimens 

 obtained by the Norwegian North Atlantic Expedition (Koren 

 and Danielssen, 1884), we find that specimens with 35 and 40 

 autozooids had stems 1,820 and 2,270 mm. in length respec- 

 tively. If we compare these specimens again we find that the 

 autozooids of the Irish specimens are very much smaller than 

 those of the specimens of the typical U.' encrinus, while they 

 agree in length with those of Marion's specimen. 



The relative lengths will be more clearly seen in the follow- 

 ing table : 



[TABLE. 



