G. AMATHIA. 67 



TULIP-FORMED. 



1. Pasithea tulipifera. Artie illations in the form 

 of clubs ; cells three in number, united on one pedicle. 

 —Plate 3. fig. 7. A. 



American seas, principally on the Jamaica coast.. 



FOUR-TOOTHED. 



2. Pasithea quadridentata^ Rampant, cells ver- 

 ticillated, four and four, with an oad one ; that in the 

 centre frequently proliferous. — Plate 3. lig. 8. a. B. 



On the fucus natans. 



AMATHIA. 



Branching Polypidom ; cells long and cylindri- 

 cal, united in one or many groups. 



The Amathias, by their numerous cells, their horny 

 and hollow stem, filled in a living state with a gelati- 

 nous and irritable substance, show the general cha- 

 racter of the Order ; they differ, however, from their 

 neighbouring genera, by their aspect, their ramifica- 

 tions, and also the form and respective situation of 

 their cells. In some species the cells are united in 

 isolated groups, resembling Pan's flute with cylindri- 

 cal reeds varying in their length ; in others all the 

 groups touch, but can easily be distinguished by the 

 unequal length of their cells : some of them have 

 their polypous cavities united at the sides, forming 

 spiral and projecting lines round the stems, to which 



