HIPPOTHOA. 295 
“This species differs so decisively from the two pre- 
ceding, that there can be no doubt of its being specifically 
distinct. The cells are calcareous; enlarged, and rounded 
at the distal, and pointed at the proximal end. Their 
direction is linear; they are attached to each other at their 
extremities, and their length is about four times their trans- 
verse diameter.” (2. Q. Couch.) 
4. HippotHoa CAssITERIDES, Couch. 
Hab. “On a stone betwixt the Scilly Islands and the 
Land’s-end.” ‘The cells are stouter and more pear-shaped 
than in HZ. divaricata, and the threads of connection shorter 
and stouter.” “At a short distance from the proximal 
lip is a small pearly tubercle, which is larger im one cell 
than another.” ‘This tubercle is very different from any- 
thing ever observed in H. dwwaricata, and constitutes it a 
distinct species.” (2. Q. Couch.) 
Genus XI. GHMELLARIA, Savigny. 
Gen. Char. Polypidom plant-like, sub-calcareous, rather soft 
and flexible when dry, much branched dichotomously: cells 
geminate, exactly opposite, united back and back with a thick 
dissepiment, a joint above and below each pair. Polypes Asci- 
dian, with elongated tentacula; no gizzard.—Dr. Johnston. 
