228 



ACTINOZOA. 



as in Pleurobrachia. Agassiz states that, in this 

 genus, only the innermost pair of paragastric 

 canals open into the oral vessels, the outer pair, 

 notwithstanding their close approximation to the 

 sides of the mouth, being destined solely for the 

 supply of the tentacular bulbs. 



In LeSueuria two tufts of tentacles, similar in 

 position to those of Bolina, but prolonged to form 

 a pair of lateral fringes, were first observed by 

 Milne Edwards, and in addition four simple conical 

 appendages, of moderate length, arise, one between 

 each of the four pairs of smaller lobes character- 

 istic of this genus. The outer paragastric canals 

 are seen distinctly to open into the canals repre- 

 senting the oral vessels, but Milne Edwards does 

 not notice the existence of any communication 

 between them and the lateral tentacular fringes, 

 which are, perhaps, nothing more than filamentous 

 extensions of the ectoderm. 



* 



LeSueuria, according to the same writer, is 

 furnished, however, with a pair ofcurious appen- 

 dages by means of which the oral extremities of 

 the paraxial canal system communicate directly 

 with the exterior. Each appendage is cylindrical, 

 short, and tubular, arising from the midst of one 

 of the principal tentacular tufts, and terminating 

 distally in four small lobes, surrounding the orifice 

 of the canal, which seems to perforate its axis. 

 Agassiz denies the existence of this opening, and 

 considers the two appendages homologous with 

 the tentacular bulbs of Bolina. 



In Leucothea a 

 apparatus occurs ; 



very complicated tentacular 

 short threads like those of 



Eurhamphcea and LeSueuria being here present, 

 in addition to three long tentacular organs, arising 





