268 



BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



opercular valve; the polypide tube is continued, proximally beneath the cryptocyst 

 cover. (After Levinsen, 1909.) 



Genotype. Siphonoporella (Membrampora) delicatissima Busk, 1861. 



Family THALAMOPORELLIDAE Levinsen, 1909. 



The tubifer zooecia have calcareous spicula in the shape of compasses and 

 bows. The ovicells are hyperstomial, with two calcareous layers, springing from 



the whole anter of the apertura ; 

 they are closed by a horizontal 

 cup-shaped chitinized operculura 

 which is connected at its basft 

 with the operculum of the gono- 

 zooecium. The opesiulae are al- 

 ways completely separated from 

 the apertura. The opercular 

 valve is membranous or chitin- 

 ized. and more or less completely 

 separated from the ectocyst by a 

 single or double chitinous scle- 

 rite. Interzooecial avicularia 

 occur. 



The principal characters of 

 this family are shown in figure 

 73. Hitherto it has been consid- 

 ered as appearing first in the 

 Miocene. The only specimens 

 which we have found occur in 

 the topmost beds of the Vicks- 



FIG. "4. Genus Thalamoporella Hincks, 1887. 



A-E. Thalamoporella rozieri Audouin, 1826. A. A'iew of 



the typical form, X 25. (After Waters, 1908.) B. Zooecia, 



X 20, of var. prominens Levinsen, 1909. C. Zooecia, X 20, 



of var. californica Levinsen, 1909. D. Zooecia, X 20, of var. 



sparsipunctata Levinsen, 1909. E. Zooecia, X 20, of var. 

 labiuta Levins?n, 1909. (B-E after Levinsen, 1909. ) 



burgian. 



The known genera are Thala- 

 moporella Hincks, 1887; Thairo- 

 pora MacGillivray, 1887, Manzonella Jullien. 1888, and ~Woodipora Jullien, 1888. 



Genus THALAMOPORELLA Hincks, 1887. 



1887. ThalamoporeJla HINCKS, Critical Notes on Polyzoa, Annals Mag.-izine Natural History, 

 ser. 5, vol. 19, p. 164. 



Characters same as for the family. 17-19 tentacles. 



Genotype. Thalamoporella (Flustra) rosien (Savigny) Audouin (1812) 



1826. 



1846. 



Range. Aquitanian Recent. 



Fossil species of this genus: Thalamoporella (Eschara) andegavensis Michelin. 



