OBSERVATIONS ON POLYZOA. 229 



the inner lines of polypides. This is probably not the 

 case, however, for colonies which have but few statoblasts 

 show as many dead polypides internally as the others. It 

 seems to depend wholly upon the age of the polypides. 



Specimens may be very roughly handled before the 

 polypides will retract, even lifting them out of the water 

 has no lasting eifect, they expand almost as soon as they 

 are replaced. After being kept in confinement some 

 weeks they become more fearful, and when alarmed will 

 remain longer retracted, but even then seem to find it 

 necessary to spread out the tentacles for air very soon 

 after the annoyance ceases, although an hour will some- 

 times elapse before the rest is expanded. 



CRIST ATELLIDJE. 



Coenoecium locomotive, entire, divided internally by 

 muscular walls. The ectocyst a transient excretion from 

 the endocyst. Invaginated fold obsolete. Statoblasts 

 annulated and spinous, the sjoines passing outside of the 

 annulus. 



CmSTATELLA. 



The generic characters not ascertained. 



Cristatella ophidioidea. 



Ccenoecium round in the young, but in the adult colo- 

 nies is frequently about eight inches long by one-fourth 

 of an inch broad ; a specimen of this length always follows 

 a sinuous course ; the smaller ccenoecia sometimes proceed 

 in straight lines, and one about an inch long crawling 

 in this way, will progress its own length in twenty-four 

 hours. 



Adidt polypides are in two rows, the tentacles of the 

 third row are not iully developed on the extremities of the 

 arms, and from the latter outwards, all stages of growth 

 are represented in the lines of buds and young polypides, 

 varying from two to five. 



The lophophore is as long as the perigastric tube when 

 fully expanded, and bears about ninety tentacles. 



