SYSTEMATIC DESCRIPTIONS. 



Order CHEILOSTOMATA Busk. 

 Suborder ANASCA Levinsen. 



A zooecial hydrostatic system is absent, but a zoarial hydrostatic system is 

 present, and is included between the cryptocyst and the ectocyst. 



The Anasca are classified under the three divisions Malacostega. Coilostega, 

 and Pseudostega. 



Division I. MALACOSTEGA Levinsen, 1909. 



The parietal muscles are attached to the cryptocyst. which if? always chitinous. 

 The operculum is a membranous valve (fig. 16). In the 

 fossil forms the frontal wall is quite or partially uncalicified. 

 The families of this division are as follows, those in the 

 first column being represented in this work : 



Elcetrimclae D'Orbig7iy, 1851. Bicellariida'e Smitt, 1807. 



Membraniporae Cami and 

 Bassler. 1917. 



Aeteidae Smitt, 1867. 



Scrupocellariidae Levinsen, 

 1909. 



Farciminariidae Busk, 18S4. 



Eucratiidae Hincks, 1880. 



fm 



oryp 



Flustridae Smitt, 1867. 

 Notamiidae Hincks. 1880. 



Family ELECTRINIDAE D'Orbigny, 1851. 



FIG. 16. Sketch illustrat- 

 ing structure of the 

 Malacostega. 



Transverse section of a 

 zooecium of a Flustrine 

 form, showing the mem- 

 branous ectocyst (fm, fron- 

 tal membrane), the mem- 

 branous cryptocyst(cn/p), 

 and the parietal muscles 

 (p. m.). (After Harmer, 

 1902.) 



Bibliography (Anatomical'). 1865, SMITT, Oru Hafs-Bryozoeruas 

 utveckling och fettkroppar, Ofversigt Kongl. Vetenskaps-Akade- 

 miens Forhandlingar, vol. 22, pi. 1, figs. 1-10 ; pi. 2, figs. 1-4. 1868, SCHNEIDER, Ueber die 

 Ent\vickelung von Cyphonautes compressus zu Membranipora pilosa, Sitzungsberiehte der 

 'Gesellschaft der naturforschenden Freunde, pi. 16. 1871, NITSCHE. Beitriige zur Kennt- 

 nis der Bryozoen. III. Ueber die Anatomie und Entwickelungsgeschichte von Flustra 

 membranacea, Zeitschrift fiir wlssenschaftliche Zoologie, vol. 21, pis. 4-6. 1875, REPIACHOFF, 

 Zur Entwickelungsgeschichte der Tendra zostericola, Zeitschrift fiir wissenschaftliehe Zoolo- 

 gie, vol. 25, pis. 7-9. 1877, BAKROIS, Recherches sur 1'embryologie des Bryozoaires, Travaux 

 de Institut de Zoologie, Lille, fasc. 1, pi. 4. 1SSO, REPIACHOFF, On the Morphology of the 

 Bryozoa (in Russian), Memoires Societe Nouvelle Russe., vol. 6. pis. 1, 2. 1000, CALVKT, Con- 

 tribution a 1'histoire naturelle des Bryozoaires ectoproctes niarins. Travaux Institut Zoologie 

 de Universite de Montpellier. Mem. S, pi. 6, figs. 7-10. 1907, BOGOLEPOW. Wachstum und Leben 

 der Kolonien der Tendra zostericola an den Gliisern der Aquarien, Zeit. Anzcitri 1 , vol. 32. pp. 

 306-316. 1908, ROHEKTSON-. The incrusting Cheilostomatous Bryn/ua of the West Coast of 



North America. University of California Publications, vol. 4. No. ">. n. i''i!i. i.l. 17. figs. 24, 25. 







73 



