34 



MEDUS:^. I. 



young individuals. The secondary branching of the lateral branches of the radial canals seems to be 

 a feature of individual variation with no relation to the developmental stage of the specimen. 



The smallest specimen, which I have examined, was found near Jakobshavn in Greenland. It is 

 14 mm in diameter. The state of preservation is not good, especially the stomach is much destroyed. 

 The bell seems to have been comparatively higher than in grown-up individuals; in the present 

 condition of the specimen the height is 8 mm. The length of the folded parts of the radial canals is 

 about 3.5 mm, the largest breadth about 2—2.5 mm. In each of the folding systems 5—6 pairs of lateral 

 folds are present; they confirm the above statement, that new lateral branches are developed not only 

 proximally and distally, but also intermediary; there are no secondary branches. The free margins of 



Table III. Synopsis of the specimens of Ptychogfina lactea examined. 



the lamellae are smooth. The length of the distal part of the radial canals, free of gonads, is 2—3 mm. 

 The number of tentacles cannot be stated exactly, but there are about 15—20 tentacles in each qua- 

 drant. The cordyli are somewhat more numerous than the tentacles (compare Bigelow 1913, who 

 states that there is a comparatively larger number of cordyli in young specimens than in older ones). 

 Some of the cordyli are situated 011 quite small tubercles as in the large individual, but some others 

 are mounted uj^on large, thick bulbs, very like tentacular bulbs of half size; still others are placed 

 in a manner intermediar\- between these two extremes. 



In order to illustrate the variation and development of the .species I have worked up the 

 above synoptic table (Table III) of the specimens examined by me. — Most of the specimens are 

 badly preserved, so that especially the number of tentacles cannot be stated. As will be seen from the 

 synopsis,, the shape of the folded part of the radial canals is subject to much variation; it may be 



