584 RECORD OF CURRENT RESEARCHES RELATING TO 



Acalophfc; as in all Craspeclota, there are transversely striped 

 muscle-fibres in the snbumbrella and veliun, and smooth fibres on 

 the sui-face of the lobes of the umbrella, and internally to the 

 gelatinous layer of the tentacles. All these muscle-fibres are pro- 

 ducts of the ectodermal cells, and are in connection with them. 

 Circular muscles are not present except in the subumbrella and in the 

 corresponding surface of the velum ; the fibrous layer which invests 

 the supporting lamella of the subumbrella is, at the four radii, broken 

 into by radial fibres, which are not transversely striated. The 

 Charybdeida) do not merely show their relationship to the Craspedota 

 by the presence of a velum, but also by the characters of their nerve- 

 ring ; this structure is, however, remarkable for its position at some 

 considerable distance from the edge of the umbrella and by its great 

 size ; at the base of the marginal bodies the nerve-ring is exceedingly 

 well developed. The mode in which its fibres enter into the conical 

 basal portion of the marginal body is a matter of some diflSculty ; it 

 might be supposed that they passed through the tissues of the wall of 

 the bell, and through the supporting lamella of the subumbrella with 

 the parts connected thereto ; as a matter of fact, their course is simjile, 

 for so soon as they have passed the supporting plate they immediately 

 bend towards the epithelial surface of the base of the marginal body. 

 Through his further details of these and of the other sensory organs 

 wc have not sj)ace to follow the author. 



As to the gelatinous substance of Charybdea, it is shown to want 

 those oval or star-shaped cells which are found in so great abundance 

 in the similar parts of Bhizostoma, Aurelia, and Discomedusa ; but the 

 rigidity of the structure is clearly increased by the number of fine 

 elastic fibres which go to make it up. The endodermal epithelium 

 varies gi-eatly in character according to its position ; it may be said, 

 as a general rule, that in the Craspedota the sui)eriorly lying epi- 

 thelium of the umbrella consists of flat cells and the inferior of 

 cylindrical cells ; the changes which are seen in it at the points where 

 the substance of the gelatinous matter of the umbrella unites with the 

 supporting lamella of the subumbrella are very interesting ; contrary 

 to what haj^pens in the Acalephfe and Craspedota, the bands are hero 

 delicate, and the radial vessels consequently form, as in Lucernaria, 

 wide pouches. In the gastric wall of the subumbrella the endodermal 

 cells are high and cylindrical, while the character of their contents 

 leads us to suppose that this epithelium, like that of the small intestine 

 of higher animals, is able to absorb albumen ; at the surface of the 

 oral infundibulum the cells are not so high, and enclose a number of 

 goblet-shaped cells, while on the oral disk the epithelial cells are 

 cylindrical in shape and provided with rounded ends ; it is probable 

 that they secrete a digestive ferment. Treating shortly of the gene- 

 rative organs. Professor Claus comes finally to the conclusion that the 

 position he had already assigned to Charybdea is the right one.* 



Halistemnia tergestinuni.t — In describing this new species, Claus 

 takes the opportunity of making some general observations on the 



* Sec tliis Journal, ii. (1879) ]>. 431. 



t ' Arbeit. Zool. lust. Uuiv. Wieu,' i. (1878). 



