1903.] MEDUSA PROM BRITISH COLUMBIA AND ALASKA. 175 



situated on an elevation on the outer side of the tentacle- base, 

 where the latter leaves the margin of the bell. ISTo otocysts are 

 present. The stomach rests with a small angular base on the gela- 

 tinous peduncle, receiving at this level the radial canals. It then 

 Avidens into a pouch, becoming again constricted into the proboscis 

 which bears the mouth below. In the living condition the digestive 

 cavity is circular in outline. In the distended condition it looks 

 thin-walled. The mouth has four short lobes which turn out- 

 ward. Each lobe is again lobulated or coarsely toothed. The 

 four I'adial canals are well marked, cylindi-ical tubes running 

 direct in their course. They pass from the angles of the stomach 

 upward along the peduncular cone to the highest point of the 

 subumbrellar space and then descend directly to the circular 

 canal of the bell-margin. Along the whole course of these radial 

 canals short lateral diverticula are given off, the ends of the 

 canals alone being free from them. Only a relatively small 

 number of diverticula on one side of a radial canal are placed 

 opposite those on the other side of the canal. None are 

 branched or have their ends enlarged in a club-shaped manner. 

 On either side of each radial canal there are about 32 of these 

 diverticula. They are shorter near the ends of the radial canals, 

 where these approach the bell-margin being mere protuberances. 

 Gradually towards the middle of the bell they increase in length, 

 until they measure about twice the diameter of a radial canal in 

 length. 



The gonads are long finger-shaped processes dependent from 

 the proximal part of the radial canals, the part most free from 

 diverticula. There are eight gonads in each of the fovu^ gi'oups, 

 the central ones being the longest and reaching to the level of the 

 velum. The outer shorter gonads may be mere rudiments. The 

 latter cannot be mistaken for diverticula, being thicker and 

 hanging free in the subumbrellar cavity. There are a few small 

 diverticula on the radial canals over the region where the gonads 

 are attached. 



Colour. — Transparent and colourless except the gonads and 

 tentacles, which are tinged a pale yellow in preserved material. 



Habitat. — Puget Sound, collected by Kincaid. 



Disctission. — In Agassiz's figure (2) of P. penicillata only 22 

 of the diverticula are on an average arranged opposite one another 

 on the sides of the radial canals. It is very doubtful if any 

 importance can be attached to the position of these diverticula ; 

 certainly their opposite arrangement is unworthy the generic 

 importance assigned it by Haeckel (18). In the generic diagnosis, 

 p. 149, he says of the radial canals of Polyorchis: " . . . . im 

 Distal-Theile mehrere Paar von gegenstandigen geschlechtslosen 

 Fiederasten tragen." Both Eysenhardt & Chamisso (12) and 

 Eschscholtz (11) represent the diverticula on the course of 

 the radial canals, in their figures of these Medusae, by cross-lines 

 drawn at right angles to the canals ; this produces the appearance 



