7g CYANEA. 



of the organs on the sub-umbrella, which is furnished with long, plicated, and furbelowed 

 membranous arms, and fasciculi of extremely extensUe, stinging, filamentary tentacles. The 

 varieties of this Cyanea have been made into numerous spurious species by Peron. 



8. Cyancea Lamarckii, Peron. Not quite so common as the last, though very frequent 

 in the Irish sea. It is easily distinguished by its more convex disk, of a deep ferruginous hue 

 in the centre, and divided at the margin into eight four-lobed triangular lobes, the eye notches 

 at their apices. The ovaries are of a rose colour. It stings equally severely with C. capillata. 

 Better figures of both these Medusa are wanted. For one of the former, the memoir of 

 Gaede, in the ' Bonn Transactions,' may be consulted ; the latter is represented in the 

 92d plate of the ' Encyclopedic Methodique, Vers' (copied from Dicquemare). 



All the genera and species of higher Pulmograda are distinguished from the lower forms, 

 to the description of which this treatise is devoted, by a much greater complexity of structure, 

 especially in the vascular system and organs of sense, and also in the arrangements of the 

 reproductive system. The vessels branch and anastomose ; the ocelli are protected by 

 complicated coverings, and are themselves of more perfect organization ; the generative glands 

 are more highly developed in the Steganopthalmata than in the Gymnopthalmata. We have 

 no instance of the Medusa or perfect state of the former propagating itself by gemmation, 

 whilst such a mode of procreation occurs in several cases, as we have seen, among the 

 latter. Taking one character with another, then, we cannot doubt that the Pulmograda 

 Steganopthalmata are higher in the series than the Pulmograda Gymnopthalmata. This is 

 borne out by an examination of the phases of development and metamorphosis of the larva in 

 the latter. The observations of Sars, Daly ell, Reid, and Steenstrup indicate that the early 

 stages of the Aurelice and Cyanece, correspond closely structurally with the perfect condition 

 of the naked-eyed Pulmogrades. 



Hitherto the genera of these two very distinct, yet proximate, tribes have been grouped 

 together, without much respect to their natural afiinities or serial order. Among the more 

 important attempts at arrangement of the Acalephse, are the systems of Peron and Lesueur, 

 of Lamarck, Eschscholtz, Cuvier, Blainville, Brandt, and Lesson. In the first of these, all 

 the Pulmograda are grouped under two tribes, termed agastric and gastric, the latter being 

 subdivided into monostomous and polystomous. Such a division is founded on a complete 

 misapprehension — one which prevailed generally among zoologists, until Milne Edwards 

 carefully examined the anatomy of Caryhdea marsupialis, which, however, in the arrange- 

 ment under consideration, was placed in the gastric division, owing to the naturalists who 

 proposed it having mistaken the whole concavity of the sub-umbrella for a stomach ! Geryonia 

 was, on the contrary, enumerated among agastric genera, the nature of the true stomach, 

 situated at the extremity of the peduncle in that group not having been recognised. We 

 find Oceania, which included a heterogeneous assemblage of naked-eyed species, placed side 

 by side with Pelagia, in a division of the Monostomous Gastric Medusee. The greater number 



