264 BULLETIN OF THE 



SIPHONOPHORA. 

 Stephanomia * Atlantica, sp. nov. 



Plate W Fig. 1. Plate VI. Figs. 18-33. 



A new species of Stej)hanomia, M. E. was taken by us at Tortugas. 



The most marked characteristic of the genus Stephanomia {Forskalia) is the 

 niultiscrial arrangement of the swimming bells. Instead of being placed 

 biserially on the stem, or with one row of bells at each end of diameters 

 passing through the axis in one and the same plane as in Agalma, Esch., 

 Ayalmopsis (sensu strictiori) and Halistemma, Huxley, the nectocalyces of Ste- 

 phanomia are arranged in several series, with their openings situated at the 

 extremities of axes or diameters passing through the nectostem in several ver- 

 tical planes, so that they seem to open on all sides, as shown in PL V. fig. 1, n. 

 The nectocalyces are much more numerous than in any of the genera men- 

 tioned, and the motion which they impart to the animal is of a more varied 

 kind. This genus is the only Physophore which has a multiserial arrangement 

 of nectocalyces on the nectostem. f 



The polypites are mounted on long peduncles (u) corresponding to the 

 " VYimperwulst " % of Agalma and related genera. From the distal end of this 

 peduncle, near the base of the feeding-polyps, hang also clusters of undevel- 

 oped tentacular knobs (j) and covering scales. The base of the polypite when 

 retracted is enlarged into a spherical body, as shown in PI. VI. figs. 20, 22. 

 This portion of the feeding-polyp is formed by the contraction of the base of 

 the polypite. The walls of the feeding-polyp are thickly pigmented (PI. VI. 

 fig. 22) near the base with dark red pigment, which renders these bodies very 

 prominent. 



The tentacular knobs (PL VI. figs. 18, 19, 21) have a single terminal fila- 

 ment, a long pedicle, and arc destitute of an involucrum. They arise from 

 tentacles as those of other Physophores. The tentacles from which they hang 



* In this account I regard Forskalia, KiilL, a synonym of Stephanomia, M. E. 

 (Vide Bull. Mus. Comp. Zool., VI. 7, pp. 132-134). 



t A single species of Physophora, P. tetretstica, is said by Philippi and Delle Chiaje 

 to have four rows of nectocalyces. This is probably a mistake. (Vide Keferstein u. 

 Ehlers. Zoologische Beitrage, p. 30, note.) 



} The base of the polypite from which tlie tentacular knobs bud. Claus, Ueber 

 Halistemma Tergestinum, p. 35. Peron's Ste2)hanomia may have been an Agalma, 

 Esch. Stephanomia, Huxley, is nearer Agnlmopsis, Sars, than it is to Stephanomia, 

 Peron. AgnlmojKis, Sars (1846), has the priority of Stephanomia, Huxley (1859). 

 Stephanomia, Milne Edwards, has pedunculated polj'pites, which are not figured in 

 Stephanomia, Peron. Milne Edwards's description is such that there is no doubt of 

 his genus Stephanomia. If we abandon Peron's generic name Stephanomia, as applied 

 by Milne Edwards, for Kolliker's later name, Forskalia, why should we retain it as 

 applied by Huxley eleven years later ? 



