I40 DISCOVERY REPORTS 



as tolerant of a wide range of conditions. As a bathypelagic planktonic animal Tetraplatia could 

 achieve world-wide dispersal through the slow circulation of the water masses in the way envisaged 

 by Coe (1946) for the bathypelagic nemerteans. 



SUMMARY 



This study of Tetraplatia volitans Busch is based on fifty-five specimens from various localities taken 

 by H.M.S. 'Research' (1900), the Discovery collections (1931-54) and the cruises of 'Carnegie VII' 

 and 'Explorer'. 



Tetraplatia is recorded for the first time, from the north-east Atlantic in the neighbourhood of the 

 British Isles, from several new localities in the South Atlantic and from three new areas in the South 

 Pacific. 



The closing-net hauls of 'Discovery 11' show that Tetraplatia occurs at all levels from the surface 

 downwards to 1000-1500 m. There is no positive indication of any marked diurnal migration, 

 possibly because of varying local conditions where the specimens were taken, but there is a suggestion 

 that the younger stages are to be found in the upper surface layers. This is in agreement with the 

 conclusions of Leloup (1935) and of Hand (1955) that Tetraplatia is wholly pelagic without a bottom 

 benthic phase. 



Tetraplatia volitans is found to be a eurythermic, euryhaline pelagic species tolerant of a wide 

 range of conditions. 



REFERENCES 



Beyer, Fredrik, 1955. A new record/ 0/ Tetraplatia {Pteromedusae). Nytt Mag. zool. Oslo, iii, pp. 106-12, 2 text-figs. 

 Browne, E. T., 1906. Biscayan Plankton collected during a cruise 0/ H.M.S. 'Research', 1900. Part ix. The Medusae. Trans. 



Linn. Soc. Lond. ser. 2. Zool. x (6), pp. 163-87, pi. 13. 

 Busch, W., 1S51. Beobachtungen iiber Anatomic iind Entzuicklung einigerwirbellosen Seetiere. Berlin, pp. 1-143. Taf. i-xvii. 

 Carlgren, Oskar, 1909. Die Tetraplatien. Wiss. Ergebn. Deutsch. Tiefsee-Exped. 1898-1899, Bd. xix. Lief. 3, pp. 75-122, 



Taf. x-xiii and 3 text-figs. 

 Coe, Wesley R., 1946. The means of dispersal of bathypelagic animals in the North and South Atlantic Oceans. Amer. Nat. 



LXXX, pp. 453-69, 2 text-figs. 

 Dantan, J. L., 1925. Contribution a I'etude du Tetraplatia volitans. Ann. Inst. Oceanogr. n.s. Ii, fasc. v, pp. 429-59, 



12 text-figs, and 2 pis. 

 Discovery Committee, 1932. Discovery Investigations, Station List, ig2g-ji. Discovery Reports, iv, pp. 1-232, pis. i-v. 

 Discovery Committee, 1941. Discovery Investigations, Station List, igji-j. Discovery Reports, xxi, pp. 1-226, pis. i-iv. 

 Discovery Committee, 1944. Discovery Investigations, Station List, 1935-7. Discovery Reports, xxiv, pp. 1-196, pis. i-iii. 

 Discovery Committee, 1947. Discovery Investigations, Station List, 1937-9- Discovery Reports, xxiv, pp. 197-422, 



pis. iv-vi. 

 Hand, Cadet, 1955. A study of the structure, affinities and distribution of Tetraplatia volitans Busch (Coelenterata : Hydrozoa: 



Pteromedusae). Pacific Sci. ix, pp. 333-48, 8 text-figs. 

 Komai, T., 1939. On the enigmatic Coelenterate Tetraplatia. Jap. J. Zool. Tokyo, viii (2), pp. 231-50, 11 text-figs, and 



pi. xxxi. 

 Leloup, E., 1935. Contribution a la repartition de Tetraplatia volitans (Busch). Bull. Mus. Roy. Hist. Nat. Belg. xi, no. 4, 



pp. 1-7, I chart. 

 PiCKFORD, Grace E., 1946. Vampyroteuthis infernalis Chun: an archaic dibranchiate cephalopod. L Natural History and 



distribution. Dana Rep. no. 29, pp. 1-40, 8 text-figs. 

 ViGUiER, C, 1885. Sur la Tetraptere (Tetraplatia volitans Busch). C.R. Acad. Sci., Paris, c, pp. 388-90. 



