J. D. Dana on Zosphytes. 343 
below, and (2) in the character of the parts below and around it. 
In the first particular, the difference is one of less general im- 
portance than has been allowed; the relative length in the Ac- 
tinie and most Actinoid corals, is between four-fifths and one- 
third ; in the Zoanthide it is between one-third and one-sixth ; 
in the Aleyonaria, between one-third and one-twentieth ; in the 
Hydroidea the stomach is sometimes much shorter in proportion 
than in many Alcyonaria, though often far longer. 
particular the difference is wide, the Actinoidea having the 
stomach suspended within the visceral cavity, and attached to the 
sides of the polyp by a radiating series of vertical fleshy lamella, 
which are wanting in the Hydroidea. The visceral cavity is a 
simple tube in the latter, and is radiated with vertical lamelle in 
the former: but these peculiarities are also connected with the 
modes of reproduction. We omit other less obvious points of 
difference 
IL. Ovarian System.—In this system, ranking in importance 
with the digestive, the absence of special organs with spermatic 
and ovarian functions, distinguishes the Hydroidea, and the ex- 
istence of such organs, the Actinoidea. No vase Ae can be of 
higher value, or more marked in its attending pecul 
Among the Actinoidea, there is a great variation in oar number 
of genital lamelle, and in the <eiee position of the two cee 
g 
may exist. There is good reason for separati 
from the Actinaria, but not for making each division esha 
in rank to that of Hydroidea. F 
. Process of Budding and Growth.—1. We find that the 
fact of species budding or ‘not budding, is not connected in Zoo- 
phytes with any peculiarity of structure that can be detected, and 
. t, the transitions are gradual and frequent. This character, 
therefore, as it indicates no difference of concentration in the ner- 
Lf tinie into the Alcyonaria ma rved 
ernaria. ve bei a four or eight- “Jobed sits pene a a eg Hea approxi- 
Mate to this Pobed character. ‘These lobes bear ro epoeti or corres- 
pond to a number; and hence analogy suggests eats that possibly in the og Sr 
each tentacle properly corresponds to two tentacles or more, or to a lobe 
tinia alluded to. This view is sans out by = te the il pt Aleyonara, the 
er not, the facts show striking differences between t 
See fu urther, Report on Zoophytes, pp. 34, 123, and this volum 
