20 



The specific name refers to the shortness of the stalk. I have found this species on 

 one ocasion only, on a species of Conescharellina. lts minute size and general proportions of 

 calyx and stalk distinguish it satisfactorily from the other 'Siboga' species. I am able to give 

 the number of tentacles, with some confidence, as 8. In this respect the present species agrees 

 with L. nitschei Vigelius 1 ); which it also resembles (judging by the figures given by that 

 author) in general form. The "height" is given by Vigelius as about 150a; but the original 

 figures give no indication of the strongly developed lateral lobes of the stomach which seem 

 to be characteristic of the 'Siboga' species. L. nitschei was found by Vigelius on Menipea 

 ternata ; the locality being Barents Sea, as may be inferred from the localities of the "host" 

 given in the same paper. 



I have recently had the opportunity of examining specimens of Loxosoma found by Miss 

 R. E. Roper in great abundance in a tank in the Dove Marine Laboratory at Cullercoats, 

 Northumberland, and recorded by her 2 ) as L. nitschei. If this determination be correct, as I 

 am disposed to think, the 'Siboga' species is probably distinct from the form described by 

 Vigelius: --a conclusion which has much a priori probability from the widely distant localities 

 of the two forms under consideration. Miss Roper has commented on the fact that the total 

 length recorded by Vigelius is less than half that of the living Cullercoats material ; and in this 

 respect I can confirm her observations. It may be worth while to record my own experience 

 of this species, as bearing on the value to be ascribed to measurements of specimens of 

 Loxosoma which have not been preserved with special care. The specimens of Miss Roper's 

 species examined by me were received alive, and were narcotised with cocaine, in order to 

 preserve them with their tentacles extended. Even in the narcotised condition there is some 

 clifficulty in killing them without contraction. In some of the individuals in which contraction 

 had occurred, the general proportions were very similar to those figured by Vigelius, the stalk 

 being much shorter than the calyx. It must be admitted that even in these cases the measure- 

 ments considerably exceed that given by Vigelius, the total length being not less than 371 ju, 

 in adult individuals; of which 243 u belong to the calyx and 128 a to the stalk. In others 

 which had been killed more suddenly with strong osmic acid the stalk measured as much as 

 320;;. in length, its breadth being noticeably less than that of the more contracted specimens. 

 The total length in an expanded specimen may be as much as 590 u.. It is thus obvious 

 that the stalk of a Loxosoma which has been preserved without being narcotised is likely to 

 be considerably shorter than the stalk of the living, fully extended animal ; although the 

 measurements of ordinary, preserved material may be of some value comparatively, since the 

 contraction probably takes place more or less equally in the majority of the specimens. 



Although the Cullercoats specimens are thus considerably larger than those from Ba- 

 rents Sea described by Vigelius I think it is on the whole probable that they belong to the 

 same species. If this conclusion is justified, the 'Siboga' specimens here described differ from 



1) VlGELtUS, W. J., 1SS2, "Cat. Polyzoa 'Willem Barents'", Nied. Arch. Zool., Suppl. Bd I, p. 19, Plate, figs 4(7, 4/S, 5. The 

 species is also recorded, doubtfully, by K. A. Andersson, on Flustra mtmbranaceo-truncata Smitt, from E. Greenland (Zool. Jahrb. Syst. 

 XVI, 1902, p. 555). 



2) ROPER, R. E. "The Marine Polyzoa of Northumberland", Dove Marine Laboratory, Cullercoats, Report for the Vear ending 

 June 13'!', 1913, p. 56. 



20 



