122 HYDKOZOA. 



of the body, presents, at its base, a globular spot of a red colour and 

 granular appearance, in which are contained numerous minute crystal- 

 line corpuscles. The whole apparatus is immediately connected with a 

 minute rounded mass, apparently of a ganglionic character, from which, 

 in some genera, filaments are distinctly seen to issue. 



(319.) In Lesueuria, for example, on carefully examining the bottom 

 of the wide excavation that exists at the anterior extremity of the egg- 

 shaped animal, four mammillated processes are apparent, each occupy- 

 ing the median line of one of the four principal lobes ; and in the midst 

 of these is seen an oculiform tubercle, situated precisely in the axis 

 of the body, which is remarkable for its bright red colour. It is of a 

 spherical shape, and presents a granular surface similar to that of the 

 brilliant red spots distributed around the margin of the disk in the 

 Medusae, which Ehrenberg designates the eyes. Immediately beneath 

 the oculiform spot is situated a subpyriform body, which is apparently 

 of a ganglionic nature ; its substance is more opake than that of the 

 neighbouring tissues, and from it proceed a great number of filaments, 

 apparently of a nervous character. These form four fasciculi, which 

 run obliquely downwards towards the inferior and external margin of 

 the principal lobes of the body : some very delicate filaments appear to 

 terminate near the base of the accessory lobes; but the greater number 

 are continued as far as the row of filiform appendages situated near the 

 margins of the principal lobes, many of them apparently giving off 

 ramifications in their course. Moreover, besides the above, a small lon- 

 gitudinal filament may be traced along the middle of each of the ciliated 

 zones, probably of a nervous character, and which give origin to a mul- 

 titude of little filaments that are distributed in a very regular manner, 

 in fasciculi, beneath each of the little transverse ridges whereupon the 

 vibratile fringes are attached, as well as to the mid-spaces intervening 

 between them : it would even seem that there is a little ganglion at the 

 origin of each of these ciliary branches; but whether this be the case or 

 not is doubtful. At the upper extremity of the body, the vertical or 

 ciliary filaments are prolonged beyond the ciliated ridges, and becoming 

 united in pairs, run towards the central ganglion situated beneath the 

 oculiform spot, with which, in all probability, they communicate. 



(320.) From the above description it will be evident that the nervous 

 system of Lesueuria differs widely in its arrangement from that supposed 

 by Dr. Grant to exist in Cydippe*, resembling more the arrangement 

 of the nerves in the Tunicated Mollusca, with which the Beroida3 pre- 

 sent many natural affinities. 



(321.) The arrangement of the generative system in the Beroeform 

 AcalephaB is very imperfectly understood ; or perhaps we ought rather 

 to say that nothing is satisfactorily known concerning this part of their 



* Dr. Grant's figure of the nervous system as he supposed it to be arranged in 

 Cydippe pilctts, is given in a preceding page, fig. 57, 2. 



