342 DISCOVERY REPORTS 



of that genus. Tamoya Jiaplonema was hitherto known in the Atlantic only from the 

 coasts of North and South America and the West Indies.^ T. alata, however, is dis- 

 tributed in the Pacific and Indian Oceans and probably in the West Indies too. Whether 

 the specimens mentioned by Bigelow (191 8, p. 400) from Florida and the Bahamas are 

 true olata cannot be made out with certainty from his too brief description. Thus, the 

 locality St Lopez is wholly isolated. The temperature at the station at a depth of 

 58-67 m. — remarkable for a cubomedusa — was about 24-6° C. 



Order CORONATAE, Vanhoeffen, 1892 



Family PERIPHYLLIDAE, Haeckel, 1879 

 Genus Periphylla, Steenstrup, 1837 



Maas (1897) and Vanhoefl^en (1903) recognize but three of the many Periphylla species 

 of Haeckel: dodecobostrycha (Brandt), hyacinthina, Steenstrup, and regina (Haeckel). 

 Mayer (1910) and Bigelow (1909, 1913) think it probable that there is but a single 

 bathypelagic cosmopolitan species, hyachithina, and that dodecobostrycha and regina are 

 merely developmental stages, varieties or local races of this species. Further studies by 

 Bigelow (1928) and especially by Broch (19 13), who examined the large series collected 

 by the Michael Sars expedition in the North Atlantic, revealed that Periphylla dodeca- 

 bostrycha and hyacinthina ought to be definitely united. In this respect both authors 

 agree, but not with regard to the species regina. Broch retained Haeckel's name (with 

 the exception of two doubtful specimens) for a few individuals of a type different from 

 hyacinthina . Bigelow, who found transitional forms between both species in the Arcturus 

 material from the tropical Pacific, arrives at the conclusion that further studies on 

 large series are necessary to decide whether regina is in fact separable from hyacinthina 

 or not. 



Among the material in the Discovery collection there are 103 specimens oi Periphylla 

 which belong, I believe, to all three forms and the study of these may help to settle the 

 question finally. The situation at present with regard to the limits of these species is 

 indeed that what one might call dodecobostrycha another might consider to be hyacin- 

 thina ; on the other hand the large dodecobostrycha and regina are not well distinguished 

 either.'^ This is especially striking in the case of the species dodecobostrycha, in which very 



1 See also the short description of two specimens of Tamoya haplonema, F. Miiller, from Swan Island 

 (south of Cuba) by Lee Boone, Coelenterata from tropical East American Seas, Bull. Bingham Oceanogr. 

 Collect., I, Art. 5, 1928. 



^ The difficulties in these determinations are considerably augmented by the fact that there are some 

 contradictions in the diagnoses or descriptions of the species. For instance both Maas (1904) and Vanhoeffen 

 (1892) agree that in P. hyacinthina the bell is relatively high and the pigmentation so dense that the gonads 

 cannot be seen by looking through the walls of the bell ; in dodecabostrycha the bell is flatter, its apex blunter 

 and the pigmentation lighter, so that the gonads may be seen more or less clearly by looking through the 

 bell walls from outside. However, Vanhoeffen (1892, Taf. i, fig. i) gives a figure of P. hyacinttiinu from life 

 showing the gonads clearly visible through the hyaline walls of the pedal zone ; similarly in Peripttylla regina 

 Maas (1897, Taf. x) shows the bell only faintly pigmented, whereas Vanhoeffen (1903) in his Valdivia 

 report shows it quite densely pigmented (PI. II, fig. 6). (See Mayer, 1906.) 



