39 



ted the attontlon of observers ; their form is not exactly tlie same 

 in the dilffiront specit^s, tliey vary accordingly, from an orbicidar 

 to an elongated oval tiguro, and enclosed in a horny shell, which 

 consists of two concave dis(.'S, united by their margins, where 

 they are further strengthened by a ring which runs round the 

 the entire margin, and is a different structure from the disc. 

 The ring is composed of cells, they are generally larger than the 

 cells of_ the disc, and of a different colour ; they are filled with 

 air, giving the ring a light spongy texture, and act as a float, 

 by which tlie statoblast wJien free is kept near the surface of the 

 surrounding water. When the statoblasts are jjlaced vmder 

 favourable circumstances for their development, they open by 

 separation from one another of the two discs or facies, and there 

 then escapes from them a young polj-zoon already in an advanced 

 stage of development, and in all essential points resembling the 

 adult individual in whose cell the statoblasts were produced. At 

 the period of its escape it possesses all the essential organization 

 of the adult, the retractor muscles are well developed, and the 

 polypido is capable of regular exertion and retraction. The 

 statoblasts have alwaj-s been viewed and described as the eggs 

 of the polyzoon in whose cell tlu^y occur. This has been a very 

 natural mistake, and Professor Allam says he fell ijito that mis- 

 take himself, but he is now convinced that they Are a peculiar 

 form of bud, and must not on any account be confounded with 

 genuine ova. They are produced in the funiculus from -n-hich 

 they are evidently developed as buds, and may generally be seen 

 in various stages of growth, arranged upon this chord, like beads 

 on a necklace, being younger as they ax^proach the distal ex- 

 tremities of the funiculus. 



The statoblasts that had already been liberated through the 

 death of some of the plumatella wore shown under the micros- 

 cope. 



Mr. Jas. Eeid produced some fresh preparations of the common 

 Echinus or Sea-hedge-hog and various impressions of fossils 

 from the iron-stone nodules in the Lenham sand-pipes, which he 

 had ret-ently collected. At the June meeting he had left a cer- 

 tain point for the consideration of the members relating to the 

 probability of some attachment of muscles to the dental process 

 in the Echinus jaw. From the construction of this process and 

 certain marks on the lever bones, an inference had been drawn, 

 that b}' muscular attachments this process might have an inde- 

 pendent movement given to it by Avhich it would have the force 

 and action of a chisel. AVithiu the last ten days, through the 

 kindness of Mr. HiUier, of Eamsgate, he had an opportunity of 

 solving the matter himself. He had determined, and afterwards 

 demonatrated to some the members, that though distinct bands 



