HYDROZOA. 61 



form and structure certain free floating bodies 

 (fig. 12), each of which, though still enclosed in 

 an outer covering, presented, on a reduced scale, 

 distinct indications of various parts observed in the 

 adult Medusid; four radiating canals, and eight 

 tentacular enlargements, being especially notice- 

 able. The full-grown Lizzia possessed twelve 

 tentacles, four single, and eight others arranged 

 in foiu alternating pairs. In the young form four 

 of the rudimei^tary tentacles were much longer 

 than the others, and it seems not improbable that 

 each of them represented one of the four pairs of 

 tentacles in the perfect Lizzia, No males of this 

 species have been observed. It is worth adding 

 that another form placed by zoologists in the same 

 genus appears to be only the detached bud of one 

 of the Corynidce. Yet, as Professor Huxley has 

 said, "it is within the limits of logical possi- 

 bilit}^ that the adult forms anatomically similar, 

 should be genetically different ; that they should 

 have arrived at a similar point by different 

 roads." 



The observations of M^Crady on the direct 

 development of an other Medusid, Cunina octo- 

 naria, also deserve attention. This creature oc- 

 curs as a parasite within the nectosacof a distantly 

 allied form, Turritopsis nutricfula, from whose 

 mouth, by means of a long proboscidiform poly- 

 pite, the young Cunina obtains its food. At an 

 early stage the Cunina appears as a clavate 

 body, presenting a short, rudely globular proxi- 

 mal, and a more attenuate, somewhat cylindrical, 

 distal, region. From the sides of the posterior 

 margin of the former, two long flexible tentacles 

 soon sprout, while, at the same time, a nutrient 



