313 
is more or less incomplete, and in S. lata (Bale) and S. distans 
Allm. it is quite absent, being only represented by the somewhat 
thickened proximal edge of the adcauline hydrothecal wall. In S. 
magnet Nutt. and S. ( Thecocladium ) flabellum Allm. it is only devel- 
oped as a narrow adcauline belt, while in S. qvadrata Nutt. and 
S. cylindritheca Allm. a corresponding belt is found in the whole 
ciicumfeience of the hydrotheca. It is broader in the dorsal than 
m the frontal surface of the colony, and, in the old hydrothecae of 
the stem I have found it closed with the exception of a round or 
pear-shaped opening. In a number of species I have found the 
diaphragma perforated by an unusually large rounded opening, for 
inst. in S. pinnata Clark, S. tricuspidata Alder, S. fruticolosa Til., 
S. Tilesii Krp., und S. infracta Krp. A large ovate opening is 
found in S. tamarisca. 
While a fascicled stem is so common a feature in the La - 
foeidae, the Campanulariidae and the Campanulinidae, it very 
i arely occurs in the Sertulariidae outside the genus Sertularella, 
namely in Diphasia alata Hincks. “ Thujaria" diaphana Allm., 
Thujaria Videns and Sertularella euneata Allm.; but it has been 
found in the following Sertularella- species: S. gayi (Lmx.), S. 
megastoma Nutt., S. catena Allm., S. pinnigera Ilartl., S. tropica 
Nutt., >S. pluma Krp., S. arborea Krp., S. crassicaulis Heller, S. 
antarctica Haiti. S. annulata Allm. and S. crassipes Allm. 
Short-stalked hydrothecae have been found in the creeping Sert. 
{Calamphora) parvula Allm., 1 ) and in a form which H ar ti au b 
has provisionally designated as Sert. tenella (?). 2 ) I think the hydro¬ 
thecae of the latter are mueh more like those of Sert Areyi Nutt. 3 ). 
The above facts, therefore, seem to show that Sertularella is 
the most primitive genus in the family Sertulariidae. Lastly, we 
must still mention that though the large plurality of the gonothecae 
iu Sertularella are ringed, the two other forms, which have been 
*) 5 . 
2 ) 19, p. 64, pi. V, tig. 24. 
3 ) 44, p. 83. 
