482 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



Versluys believed the animal had an operculum with a single abcaul- 

 ine flap. Nutting (: 04, p. 53) was inclined to think there were two 

 flaps on his badly ruptured specimen. Material in good condition 

 shows that there are two large lateral projections from the edge of the 

 hydrotheca and a smaller adcauline one. The three parts of the oper- 

 culum meet in ridges along lines passing from the centre of the opening 

 to the projecting points. 



Genus THYROSCYPHUS Allman, 1877. 

 Thyrocyphus intermedius (new species). Figures 33-36. 



My only collection of this new form is from the eel grass of a shallow, 

 muddy cove of Mangrove Bay (lat. 32° 18' 10", long. 64° 51' 30"). 



Hydrothecae usually sin- 



^oJ^ 



34 



35 3G 



Figures S-S-^JO. Thi/roscyphus intermedius. 



Figure 33. Colony (X If), 



Figure 34. Hytlranths, sliowing operculum (X 7^) 



Figure 35. Colony (X 10). 



Figure 36. Hydrantli (X 60). 



gle, with pedicels one 

 and a half millimeters 

 long (Figure 36). A 

 small proportion have 

 two or three hydrothe- 

 cae, whose annulated, 

 geniculate, erect stems 

 resemble elongated sto- 

 lons (Figure 3a). A 

 terminal hydrotheca is 

 found at one end of the 

 axis and one or two 

 others are attached at 

 geniculations. The an- 

 nulated pedicels are 

 shorter than hydrothe- 

 cae ; when single, not 

 more than a third as 

 long. 



Hydrothecae (Figure 

 r)6) are more than twice 

 as long as wide, nearly 

 cylindrical, marked by 

 eight or more annula- 

 tions, and tapering 

 slightly toward the top. 

 An operculum is formed 

 by the bending of the 



