REPORT ON THE SIPHONOPHOR^E. 205 



unpublished plate of Lesueur, founded upon it a new genus, Apolemia uvaria (1829, 1, 

 p. 143). Blainville copied in 1834 a part of Lesueur's splendid figures in his Actinologie 

 (24, pi. iii. fig. 1), and Lesson copied the description of it and named it "Apolemia 

 Lesueuria" (3, p. 518). I myself obtained in 1878 at Paris, owing to the kindness of 

 Professor Perrier, a copy of Lesueur's beautiful plate, and on comparing it with the 

 Mediterranean Apolemia uvaria, was convinced that these two forms are not identical, 

 as preceding observers had supposed, but belong to different species or even genera. 



The Mediterranean Apolemia uvaria, the largest Physonect of this sea, was described 

 in the years 1853 to 1863 by Kolliker (4), Vogt (6), Gegenbaur (7), Leuckart (8), and 

 Claus (35). The descriptions of these authors together give a satisfactory idea of this 

 interesting type of the family. It differs from the Apolemia lesueuria in the dioecious 

 conn and the naked internodes of the siphosome, which in the latter are densely covered 

 with innumerable bracts. Since the corms, too, in this latter are monoecious, I separate 

 it as Apolemopsis lesueuria. 



Closely related to this latter seems to be an Apolemid from the Tropical Pacific, which 

 Mertens observed near the Caroline Islands, and Brandt described in 1835 under the 

 name Apolemopsis clubia (25, p. 36). Comparing the accurate figure of it, which 

 Mertens had drawn from life, with the plate of Lesueur, I think these two forms belong 

 to the same genus, but are distinct species. 



During my voyage through the Indian Ocean, from Aden to Bombay, in 1881, I 

 captured a single but complete specimen of the interesting new Physonect, which is 

 figured in PL XVIII. figs. 1-7, of this Eeport, under the name Dicymba diphyopsis. 

 The composition of the corm and the form of the single organs are almost as in the well- 

 known Mediterranean Apolemia uvaria ; but there are two important differences ; the 

 nectosome is composed of two opposite nectophores only (as in Praya and Diphyes), and 

 the cormidia are monogastric, with a single siphon and tentacle (as in the Diphyidae and 

 Agalniidae). This Indian Physonect may therefore be regarded as the type of a new 

 subfamily, or even family — Dicymbidae. 



Nectosome. — The swimming apparatus of the Apolemidse is similar to that of the 

 Agalmidse, but differs from it in two characteristic peculiarities. The pneumatophore is a 

 simple invagination of the exoderm, without radial pouches ; and the nectophores 

 beyond it are provided with tentacles wanting in the Agalmidas. The number of 

 nectophores is different in the two subfamilies ; Dicymba, the single known type of the 

 subfamdy Dicynibidse, possesses only two large opposite nectophores, similar to Praya 

 and Diphyes, and approaches in this as well as in other respects to the Diphyidae. The 

 subfamdy Apoleniopsidse, represented by Apolemia and Apolemopsis, on the other hand, 

 has two obliquely opposite series of alternating nectophores (four to six pairs or 

 more), similar to the Polyphyidse and AgalrmVUe. The long and thin contractile filaments 

 which arise from the trunk of the nectosome between the single nectophores are 



