1910] "Robertson: Cyclostomatous Bryozoa. 255 



seven or eight, then gradually aarrowing again to two zooecia. 

 Branching extremely irregular, following qo particular method ; 

 arising both from lateral and ventral zooecia al any poinl of an 

 internode and becoming more profuse toward the distal ends of 

 the branches. Basis rami (6a. r.) often of greal length, and as 

 in Crisia being merely the proximal portion of those zooecia 

 which have developed a non-calcified, somewhat thickened ehit- 

 inous ring in the wall, serving as a flexible joint. Joints {j.) 

 large, light-colored, yellow or amber. Zooecia long, slender, 

 connate for part of their length, curving sharply forward, and 

 projecting frequently half their length; proximal portion 

 scantily punctate, distal portion less distinctly punctate; 

 number in an internode not constant, arrangement more or less 

 alternate, except in the oiecial internodes where it is regularly 

 alternate. Ocecial inU ninth s always longer and broader than 

 those that do not produce ovicells; growing rather suddenly 

 broader by an increase in the number of rows of zooecia at the 

 point where the ovicell begins, and growing narrower toward the 

 distal extremity. On tin (oe.) found on the younger internodes, 

 numerous, large; formed by an inflation of the ventral wall, 

 extending partially over and between the zooecia whose distal 

 extremities project, through the ocecium, but unaffected appar- 

 ently by its growth around them; beginning about one-fourth 

 the length of the internode from the joint, and occupying its 

 middle half; embryos numerous. Oosciostome below the summit 

 of the ovicell; tube of oceciostome {oest. I.) prominent, arising 

 beside a zooecium near the distal end of the ovicell, adnate to it. 

 for part of its length, then growing smaller than a zoceeial tube 

 and curving freely forward. Oceciopon [oep.) circular, directed 

 upward. 



Adult ovicells frequently possess a large number of larvae 

 in all stages of development. Owing to the spindle-shape of 

 the ovicell, its interior is divided into long, narrow passages 

 which are the spaces between the zoiecia ; in these the embryos 

 develop in long, narrow chains, or strands, resembling beads 

 strung on a string. In reality they are held together by strands 

 of tissue which form a network that holds the larvae in a chain 

 and holds the chains together more or less closely. The question 



