SALPIDiE. 51 



" The mode iu which the republic is linked together is observed 

 to be constant in each species ; and it is sufficiently remarkable 

 in this one to distinguish it from the rest of the genus as far as it 

 is yet described. Each individual adheres to the preceding by a 

 regular sequence of superposition lengthwise, so that the whole 

 forms a long simple chain ; the adhesion continuing, as in the 

 ovarium, for some time after hatching. They were found from the 

 middle to the latter end of August, and always linked together. 

 It is probable that their separation takes place at a later season 

 of the year, but I did not observe them in that state. The indi- 

 vidual is amongst the most simple in shape of those yet described, 

 presenting an oval-lanceolate and slightly rhomboidal flattened 

 figure, without appendages. The anal opening is of a bright 

 brown and circular, being placed at some distance from the ex- 

 tremity; and when the chain is linked together, all these aper- 

 tures are directed the same way. The animal is perfectly hyaline 

 and tender, and the adhesion of the chain so slight, that the indi- 

 viduals are easily separated. The act of swimming is known to 

 result from the introduction and emission of water by each ani- 

 mal ; and as the republic swims together by an undulating mo- 

 tion resembling that of a serpent', the chain often extending to 

 many feet in length, it is evident that this motion must arise 

 from the unequal manner in which the different individuals act 

 throughout the whole line. 



" The species now described is most analogous to the aS'. 'polycra- 

 lica and to the S. confederata of Porskahl. It differs, however, 

 from the former in the want of the caudal denticle, in its hyaline 

 appearance, and in the absence of the rigid portion which attends 

 that one. From the latter it is readily distinguished by its 

 longitudinal concatenation, since, in that species, the individuals 

 adhere by their sides, so as to form a row in a lateral direction, 

 while there are at the same time important differences in the 

 structure of the two. 



"I had occasion to remark of this animal, that, like the Me- 

 dusce and analogous tribes, it cannot bear to be confined in a 

 limited portion of water, as it died, even in the ship's bucket, in 

 less than half an hour ; a very remarkable circumstance in the 

 economy of these imperfect animals. 



" Hitherto, this genus is only known as the inhabitant of hot 



