MEDUSAE. 163 



Erssea angustata, sp. nov. 

 Plate 10, fig. 1,1. 



The animal is about 6 mm. in length. The anterior covering-scale is 

 irregularly pyramidal and is provided with a deep fissure upon its ventral 

 nice, which embraces the upper portion of the large posterior swimming- 

 bell. The upper apex of the anterior covering-scale is usually pointed, and 

 the two dorsal edges are quite sharp and angular. The phyllocyst is long 

 and sometimes contains a highly refractive " oil globule," situated near its 

 distal extremity. The single feeding polypite is quite long and is capable of 

 being extended beyond the lower edge of the covering-scale. A group of 

 tentacles arises from its side, and immediately above this there are one or 

 two gonophores in various stages of development. The entoderm of the 

 polypite and phyllocyst is rose-colored, while the terminal nematocyst bat- 

 teries of the tentacles are orange as in the Diphyopsis generation. The 

 posterior swimming-bell is rectangular in cross-section with four sharp-edged 

 longitudinal ridges, which are often serrate. A deep trough-like longitu- 

 dinal groove extends down the ventral side of the swimming-bell. The 

 bell-cavity is irregularly conical, and the velum is very powerful. There 

 are four straight, narrow, radial canals and a simple, slender, circular 

 canal ; and these are placed in communication with the gastrovascular 

 space of the polypite by means of a short, straight duct. There is no manu- 

 brium within the swimming-bell. 



This Siphonophore may readily be distinguished from the Atlantic form 

 by its pink coloration, the Atlantic species being green. 



Abyla quincunx Chun. 



Abyla quincunx Chun, C, 1897 ; Verhandl. d. Deutsch. Zool. Gesell., p. 71, Fig. 13. (Atlantic 

 form.) 



Plate 11, figs. 46, J.7. 



