332 ANNUAL OF SCIENTIFIC DISCOVERY. 







eludes all known species of existing coral zoophytes. Out of the 444 

 known species (excluding the Alcyoneria), 233 are new species, first 

 described by the author, and of the remaining 211, 122 are redescribed 

 from specimens. To the genus Madrepora, previously numbering 20 

 species, 52 new species are added, and 12 of the old ones redescribed. 

 The 30 known species of Astreeae are increased to 62 ; the 4 of Eu- 

 phylise, D., to 15; the 17 Fungidse to 60; the 57 Madreporidee to 

 141, and 34 of the old species are redescribed. An examination of 

 the animals made it. in general possible to give the descriptions a zoo- 

 logical character, so that the science is at last rescued from being a 

 mere systematical arrangement of animal secretions. Species hardly 

 distinguishable in the corals were found very different in the animals, 

 and by this means those erroneously referred have been properly 

 classed. 



NEW SPECIES OF AMERICAN MEDUSA. 



AT a meeting of the Boston Society of Natural History, Prof. 

 Agassiz gave a description of a new Naked-eyed Medusa, belonging to 

 a new genus, which he would call Rhacostoma Atlantic/urn. Instead 

 of the usual structure in these animals of four chymiferous tubes 

 reaching a peripheral vessel, with eight or ten tentacles, there are in 

 this animal over 100 appendages to the mouth, and 500 or 600 on the 

 circumference. The mouth is so wide that it has been supposed to be 

 wanting ; the union of the appendages to the mouth in a firm cord 

 forms an alimentary cavity for the animal ; these are formed of very 

 large polygonal cells, which give a remarkable power of enlarging 

 and contracting this cavity. This is the largest of the family. The 

 circular tube of the margin is a nervous cord ; at night it emitted light, 

 and when stimulated the whole outline of the nervous system was 

 seen as an illuminated diagram of a golden-yellow color ; so that in 

 this animal, at least, the phosphorescence took place in the substance 

 of the nervous cord. The characteristics of the animal are the extra- 

 ordinary number of the tubes radiating from the central cavity, and its 

 remarkable power of enlarging and contracting. 



MUSCULAR STRUCTURE OF MEDUSAE. 



PROF. AGASSIZ in a recent study of the Medusae has been able to 

 make out a distinct muscular structure. It consists of three systems 

 of fibres, one superficial, which has never before been observed, just 

 under the epidermis, the others more deeply seated. The external 

 layer is made up of circular and vertical bands of fibres, surrounding 

 the whole mass like the net of a balloon, and capable by their contrac- 

 tion of changing its shape and reducing its size. The vertical bun- 

 dles alternating with the radiating tubes are by far the strongest. 

 The fibres upon the inner surface of the disk are disposed in two 

 layers, one of circular, and the other of vertical fibres. The former 

 lines the cavity, the latter is situated between the circulating tubes. 

 By the contraction of these last, the eye-specks can be moved. In the 



