^RT. 14 FOSSIL AND RECENT BRYOZOA — CANU AND BASSLER 61 



The ectocyst entirely surrounds the zooecium; a sclerite Httle thick- 

 ened surrounds the terrnen of the mural rim. The aperture, semi- 

 elliptical and transverse, is bordered with a strong sclerite in which 

 the sclerite of the opercular valve is exactly inserted. We are obliged 

 to separate these two sclerites on our figures in order to show their 

 independence, but on the specimen it is impossible to separate them. 



The opercular valve is supported laterally on the two condyles of 

 the opesium. It is always removed from the mural rim, especially 

 laterally. The attachments of the opeciular muscles are indicated 

 in the opercular preparations by two black points rather removed 

 from the hinge joint of the valve. 



The opesium, very constant in its general form, is very irregular 

 in its dimensions; the two lateral condyles are large and salient. 

 The mural rim is salient and the cryptocyst is somewhat granulated. 



The onychocellarium is oval, often triangular in its distal portion. 

 The two membraneous wings of the mandible are very fragile and 

 we have not yet been able to make a good preparation of them. 



In 1920 we determined as Floridina antigua a Jacksonian species 

 much larger and much more vigorous. We were deceived by the 

 enlargement of the figure of Smitt, who has never given the magnifica- 

 tion of his drawing. It is necessary then to change the name of the 

 fossil species to which we here apply the new name Floridina rohusta. 



,, ^ r^ • J/io = 0.14-0.16 mm. 



Measurements. — Upesiumi^ 



^ lZo = 0.20 mm. 



fis = 0.40-0.50 mm. 



Zooecia 7 „ .„ 



Us = 0.40 mm. 



r. 1 , fy^o = 0.08 mm. 



Opercular valvei , ^ ^ ^ 



Uo = 0.10 mm. 



r\ -L. ^A ' f^on = 0.30 mm. 



Biology. — Our living specimens were ovicelled April 9, 1885. The 

 ectocyst only is pigmented with a clear brown. This color is not 

 constant and depends on the substratum, for one of our specimens is 

 rose colored on one side and green on the other, according to the 

 color of the nullipore which it encrusts. The greater part of the time 

 the pigmentation appears to be that of the phytoplancton. To 

 the present time this species has not been dredged from great 

 depths. 



Occurrence. ^Albatross Station D. 2405, Gulf of Mexico; 28° 45' 

 00'' N.; 85° 02' 00" W.; 30 fms.; gray sand, broken 

 coral. 

 Albatross Station D. 2639, Straits of Florida; 25° 04' 



50" N.; 80° 15' 10" W.; 56 fms.; coral sand. 

 Fowey Light, 15 miles south of Miami, Fla.; 40 fms. 

 Florida, 47-71 meters (Smitt). 

 Plesioty pes. —C&t. Nos. 7495, 7496, U.S.N.M. 



