1910] Robertson: Cyclostomatons Bryozoa. 233 



84. Crisia franciscana sp. nov. 



PI. IS, figs. 1. 2, 3, 4. 

 Crisia occidentalis Robertson. 1903. 



Zoaria composed of numerous, delicate, branching tufts 15 to 



20iimi. in height; found at low tide on rocks and mi seaweed, 

 attached by flexible rootlets (pi. 18, fig. 1). Internodes (fig. 2, 

 int. i, consisting of a single zooecium giving rise to a branch {or.) 

 on each side. Each branch arising in a basis rami [bit. r.) 

 adnate to the zocecium giving origin to it. Joints (j.) light- 

 colored at the growing tips, but becoming black with age, a clump 

 of this species having a distinctly speckled appearance even to 

 the naked eye. Zooecia (zoe.) consisting of rather long, slender, 

 calcareous tubes, usually slightly curved or concave on the 

 ventral side; sparsely punctate, the distal end having a slightly 

 ringed appearance. Ocecia (oe.) elongated, narrowed below, 

 much inflated above. Ooeciostome (oest.) large, its tube (oest. t. ), 

 prominent, bent backward. Oceciopore {ocp.), circular, directed 

 backward and slightly upward. Ocecial internede consisting 

 typically of three members, the first being an ordinary zocecium, 

 z 1 , arising in a basis rami; the second being the ocecium (oe.), 

 arising on z 1 in a slender cone (oe. c), larger than, but cor- 

 responding to a basis rami: the third member being a non- 

 flexible zooecium, z s , adnate to the ocecium throughout its whole 

 length. 



The zoarium of Crisia franciscana has a very distinctive 

 appearance due in part to its coarse, dense growth, but in larger 

 part to the great number and regularity of its black joints. It 

 is this species whose embryology was investigated by the present 

 writer ( :03) under the name of C. occidentalis. That name 

 being preoccupied, (Trask '57), the specific name franciscana is 

 now given it, since the region where it is most abundant is on the 

 shores of San Francisco Bay. 



In the discussion of the phenomena of the embryology of this 

 and related species, mention was made of a structure first noted 

 in the ovieell of C. franciscana, and afterwards found to be 

 present in the ovieells of both C. edwardsiana and C. geniculata. 



