68 ZOOPHYTES. 



as may be seen of others, the lower portion whence the cilia originate is 

 meantime free. Here, as we know, the mouth or proboscis of the Medu- 

 sarian race is situated. In the under surface four cruciform organs were 

 apparent. But the difficulty of ascertaining relative position is never to 

 be forgot ; and, in fact, organs apparently below in such creatures may be 

 in the middle, or actually above. 



As in some other Medusae, the ciliary, or tentacular organs, resemble 

 knotted cords. Each pair originates from a prominent knob or button on 

 the margin of the cavity in the under part ; and a black speck, like an eye, 

 is conspicuous at the root of each tentaculum : there are, therefore, eight 

 in all. The transparent convex surface of the animal is crossed by two 

 darker lines at right angles, as if dividing it into quarters, and terminat- 

 ing in the four buttons or knobs on the margin. 



The opacity of this creature during its earlier stages is not such as 

 entirely to intercept the light, though its transparence refines in proportion 

 to the evolution of its organization. Thus, the cross lines running from 

 what was conjectured an orifice is discovered to be four vessels, wherein a 

 fluid carries a number of black particles down to the marginal knobs below. 

 It rather appears also, though I could not satisfy myself of the fact, that 

 the current may pass in another course around the margin. 



We should be much deluded, as well as our fellows, in believing that 

 sufficient opportunities are afforded for similar observations by the Me- 

 dusa, free of the zoophyte, and swimming at large. On the contrary, they 

 can be effected only while immaturity yet restrains the animal to its pris- 

 tine site ; and where, during progressive evolution, the microscopical focus 

 can be accurately adjusted for distinct vision. The motion of so restless 

 a being, when liberated, renders correct observation incompatible with 

 that condition. 



One of the pyrula seemed to be united to a hydra, just at the orifice 

 of the twig from which it issued. Circulation manifestly advanced in both. 

 Black particles were carried up as well as down the neck of the former 

 the pyridum ; and during their descent, a current was obviously convey- 

 ing black particles up the body of the hydra ; something similar seemed 

 to be going on in an isolated pyrulum, where there was no hydra. 



