830 MR. E. T. BROW.VE O.V BRITISH MEUUS.E. [Xov. 16, 



55 mm. in diameter, keeps pace with the growth of the umbrella and 

 becomes longer and more funnel-shaped. The mouth, as in all 

 these specimens, has a considerable number of folds and is capable 

 of considei'able expansion (35 mm. in diameter when expanded). 

 There are 43 tentacles of various sizes, and between every two tenta- 

 cles usually one large and two small marginal bulbs, and between the 

 latter several marginal vesicles. The radial canals (153 in number) 

 nearly all enter the ring-canal. The genital bands are very con- 

 spicuous. The velum is about 4 mm. broad. 



No. 6. Umbrella J60 mm. in diameter. 



This is the largest specimen of the series, and to judge from the 

 immature condition of the ova the medusa has not yet reached its 

 full development and probably grows to a larger size. The 

 diameter of the stomach is 53 mm., and the mouth has a very 

 large number of folds. There are 56 tentacles, and between every 

 pair of tentacles usually one large and two small bulbs, which may 

 develop tetitacles later on. The radial canals are only 88 in 

 number and nearly all join the ring-canal, and nearly all have 

 generative cells in different stages of development. 



The following is a general description of the different organs of 

 the specimens above described : — 



The Stomach and Mouth. 



The stomach is remarkable on account of its size ; the upper 

 part, as already stated, is circular and convex in shape ; the con- 

 vexity is more marked in the larger specimens. Iii shape, the 

 stomach is like a short, broad funnel with the side marked by 

 longitudinal lines, like frosted glass, which alternate with the 

 openings of the radial canals. The lines extend from the base 

 of the stomach up to the edge of the mouth. The closing of the 

 mouth is effected by the wall of the stomach becoming spirally 

 twisted. When the mouth is closed the stomach becomes more 

 elongated and the twisted portion forms a kind of oesophagus 

 (" Schlundrohr" of Haeckel), just as in Polycanna fungina, 

 Haeckel (Taf. xiv. fig. 4). The mouth does not always hang in 

 the centre of the umbrella-cavity, but at times moves verj' slowly 

 round and round the margin of the stomach. The edge of the 

 mouth, in the smallest specimen, has simple folds, which become 

 more complex in the larger specimens. 



The Radial Canals and Generative Organs. 



AUman gives in his Monograph (p. 79) an excellent diagram 

 showing the development of the radial canals of an ^Equorea (prob- 

 ably ^2t«orra/o/-sA:«?€n, Forbes). The specimens taken at Valencia 

 show that the radial canals do not develop in any definite order. 

 In the smallest specimen about one-third join the ring-canal, and 

 the remainder show various stages of growth — some of them are 

 only just leaving the stomach. The number of canals appears to 

 be very variable, as the largest specimen has only 88 canals, and 



