ART. 14 FOSSIL AND KECENT BEYOZOA CANU AND BASSLER 155 



outlining the two lucidae and attached to the marginal sclerite. 

 The two lucidae indicate the place of the cardelles. A transverse 

 and thick sclerite placed below the axis of rotation serves probably 

 as attachment for one of the walls of the compensatrix. The dimen- 

 sions are not constant, for the aperture increases in size from the 

 center to the circumference. 



The ancestrula is frequently a zooecium larger than the adjacent 

 zooecia; it is surrounded by six smaller zooecia, but their structure 

 is identical and normal. 



Biology. — Mamillopora cupula is a floating species. It has not been 

 dredged in the high seas and appears to prefer the vicinity of the 

 shores. The geometric regularity indicates that it can easily turn on 

 its axis either to accomodate itself to the aquatic movements or to 

 search for nourishment. It can at its pleasure rise or descend, but 

 it is absolutely deprived of organs 

 of motion. In our sections we have 

 not discovered a substratum for the 

 fixation of the larva, as in Conesch- 

 arellina or Flabellopora. The larva 



is not fixed then (as in Lunulites) ^~a~^ ^ "c" 



but it is transformed into a swim- fig. 35.— mamillopora cupula smitt, 1873. 

 ming larva. This is a very curious ^-^- ^^^"^ "°^^^ °^ °^^"^^^"' ^ '' 

 phenomenon, indicating a larval structure very different from that of 

 the other bryozoa.. The discovery of the larva is therefore very 

 desirable. 



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



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



broken coral. 



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



Albatross Station D. 2411, Gulf of Mexico; 26° 33' 



30" N.; 83° 15' 30" W.; 27 fms.; fine white sand, 



black specks. 



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



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

 Florida, 48-110 meters (Smitt). 

 Miocene: Rio Cana, Santo Domingo. 

 Plesiotypes.— Cat. Nos. 7541, 7542, U.S.N.M. 



Family CHAPERIIDAE Jullien, 1888 

 Genus CHAPERIA Jullien, 1888 



CHAPERIA GALEATA Busk, 1852 



1923. Chaperia galeata Canu and Bassler, North American Later Tertiary 

 and Quaternary Bryozoa. Bull. 125, United States National 

 Museum, p. 52, pi. 34, figs. 8-10. (Bibliography, geologic and 

 geographic distribution.) 



Our specimens are ovicelled, ectocysted and ornamented with 

 their distal spines. They are rare. 



