THE MORPHOLOGY OF THK CHEILOST( >MATA. 313 



back to backj alternately, all the zofficia looking towards one 

 or the other edge of the branch. The zooecial characters 

 agree with those of C. sinclairii. There is a large compen- 

 sation-sac, opening by a median pore, which is transversely 

 elongated, but the concavity of which is on the proximal 

 side. Between this and the operculum are two fenestrae, 

 placed as in 0. sinclairii. In addition to two lateral horns, 

 similar to those of C. gracilis, there are three other oral 

 spines placed more distally. 



Ichthyaria ocnlata, Busk ^ (fig. 59). 



There can be no doubt that this species was incorrectly 

 placed by Busk in the Bicellariidte, a family with which it 

 appears to have no affinity. Its more natural position would 

 probably be in the Calwelliidae,^ with which it agrees in the 

 characters of its zooecium and of its ovicell. The zocecia are 

 arranged in a double alternate series, all facing in one 

 direction. The median pore (?»..p.) is cii-cular, and is situated 

 on the axial side of the middle of the zooecium. It is con- 

 nected with the operculum by a longitudinal suture (.<?.), 

 on each side of which is a funnel-shaped fenestra, as in 

 Calwellia. In correlation with the asymmetrical position 

 of the median pore the abaxial fenestra is much further from 

 the suture than is the other one. There ai'e one or two 

 distal fenestrae, probably indicating- the former development 

 of oral spines. 



The compensation-sac (c. s.) is arranged as in Calwellia. 

 It opens by the median pore, and tlierefore ends at some 

 distance from the opei'culum. The parietal muscles (p.m.) 

 occur as a series of definite groups, as in Flustra. Calcifi- 

 cation is deficient along a line extending the whole length 

 of the basal side of the zooecium. The line is narrow for the 

 greater part of its course, but dilates at each end. The 

 older parts of the colony are supported by a calcareous 



1 T5usk (1884), p. 4G. 



- Waters (ISSS, j). 10) places it in Calwellia, a view wiiicli seems not 

 uureasonable. 



