96 Mr. Patterson on the Cydippe Pomiformis. 



entire, the membrane connected the tubular rays to their extremity, where the 

 fin presented a slightly rounded outline." 



In C. Pomiformis the cilia present appearances very dissimilar to the above. 

 In many individuals the filaments are not connected by any membrane, but 

 appear numerous, flat, tapering, and slightly recurved towards the extremity. 

 In others they are covered by a transparent membrane, divided as usual into 

 two equal parts, and showing in each half but one or two divisions. They 

 never exhibit an entire and unbroken surface, nor a continuous and regular 

 margin. It was natural to suppose that a membranous covering might origi- 

 nally have existed in all, but had been abraded or torn, and thus caused the 

 apparent diversity which the cilia exhibited in the number of their sub- 

 divisions ; but this conjecture was shaken, by observing that specimens of less 

 than the average size, and which might be presumed to be young, presented the 

 same want of uniformity. The dissimilarity which prevails in this particular 

 among different Beroes, will however be better estimated by a glance at the 

 annexed figures, than by any detailed description. 



The entire cilia, never for more than a moment remain perfectly at rest, tm- 

 less when the animal is in a very exhausted state, and may hence be presumed 

 to be organs of respiration as well as of locomotion. Sometimes, however, those 

 of one or two continuous bands will vibrate, while all the remainder are still ; or 

 be at rest, while all the others are in motion. At times a slow vibration will 

 commence at one extremity of a band, and pass along it, like the wave which 

 can be impelled along an extended piece of cloth, or like the undulations of a 

 fluid. Hence it is obvious that the Beroe can direct the aqueous currents which 

 pass along the base of the cilia into any particular band, and can regulate at 

 pleasure the velocity of their undulations. In the larger species, which I have 

 named Bolina Hibernica, these currents are very conspicuous, and may be 

 seen under* each band, one ascending, the other descending at the same time 

 with great regularity. 



* The size of this ciliograde varies from little more than half an inch to nearly two inches dia- 

 meter ; its figure is diversiform, being nearly round, oval, or cylindrical, but most generally some- 

 what compressed. The lobes at each side of the mouth, at times very protuberant, giving to the 

 animal a rudely cordate form, like the Mnemie de Schweiger. (Vid. Blainville, pi. 8, fig. 4.) The 

 surface smooth. 



There are eight rows of cilia, the alternate ones much shorter than the others. The cilia are 



