16 



details, differ in their result to a certain extent from those of Prof. 

 Forbes, it is to those portions that I am desirous, in the following 

 remarks, more particularly of directing your attention. 



This Medusa is not so perfectly transparent as many of its conge- 

 ners, and its texture is more solid and firm to the feel than it is in 

 many others. It is very active and vigorous in its movements, and 

 may be kept alive some time with a little care. Some idea of its 

 form and appearance may be derived from fig. 1 a, and magnified fig. 

 1 b. Few objects can be conceived more elegant and graceful in 

 form and colour than the tiny, ruby-tinted Turris neglecta, gently 

 rising and sinking, or suspended in its native element ; its long fila- 

 mentous tentacles, extended to their full length, waving about and 

 surrounding the creature as it were with a delicate halo. The disk 

 of all these Medusce appears to be composed of two distinct mem- 

 branes or layers, of which the external is termed the umbrella, and 

 the internal or inferior, the subumbrella. To the margin of the disk 

 are appended the tentacles, and in some cases other organs, about 

 which more will be said in the subsequent observations upon the 

 Thaumantias. From the centre of the subumbrella in most genera, 

 depends, like the clapper of a bell, the peduncle, which contains the 

 stomach or digestive cavity, and in some genera also supports the 

 ovaries or reproductive glands. Within the margin of the disk, there 

 is in many cases, but not so conspicuously in all, a wider or narrower 

 strip of membrane, termed the velum or veil ; and within the sub- 

 stance of the rim there is always a canal running round the entire 

 circumference, and from this marginal canal four or more radiating 

 canals pass, in the substance of the subumbrella or beneath it, to- 

 wards the base of the peduncle, and which canals can, in many 

 instances, be seen, and in most are supposed to open directly into the 

 stomach or cavity communicating with it. I shall proceed to de- 

 scribe these various parts in Turris neglecta in the order above indi- 

 cated. 



The external integument of the disk, or the umbrella, is thick and 

 firm, presenting faint indications of its being composed of cells mostly 

 elongated and prismatic, but under more superficial examination it 

 appears to be structureless : the external surface is covered with 

 minute, circular, granular, slightly-raised spots, which constitute a 

 sort of imperfect cuticular layer, but these scales or spots are not in 

 close contact. The subumbrella is much thinner, and is connected to 

 the former by a lax cellular tissue. It is composed almost entirely 

 of muscular fibres, being in fact, it may almost be said, a muscular 



