AKT. 14 FOSSIL AND RBCElsrT BRYOZOA^ CANU AND BASSLER 129 



some large and some smaller cells. The smaller cells are frequently 

 deprived of avicularia. 



The peristome is indented by a rimuie spiramen but the ovicelled 

 zooecia do not bear one and probably have no polypide. Our speci- 

 mens, unfortunately not being preserved in alcohol, we have been 

 unable to study their anatomy. On the interior there are parietal 

 dietellae as in the Adeonidae. By transparency, there are large 

 interareolar costules and a kind of lyrule often garnishes the spira- 

 men sinus of the peristome. The ovicell bears two pores invisible 

 exteriorily. 



Two flabelliform muscular bundles move the mandible, which is 

 strongly chitinized on the borders. 



Biology. — The colony frequently encrusts radicells of algae which 

 give to it its tubular appearance. They creep also on nullipores and 

 on Serpulae and cover large surfaces. Man}^ 

 lamellae are sometimes superposed. 



The color is rose, reddish purple, or reddish 

 violet. 



Affinities. — At first glance this species may 

 be confused with. ScMzopodrellaJlondana Osburn, 

 1914, but differs from it in its large endozooecial 

 ovicell, in its pleurocystal and not tremocystal 

 frontal, and in its avicularium with inferior (and fig. 26— metearabdotos 

 not superior) concavity. Its large unguiculated unguiculatum, new 



, . ,.™ . ■•, ., n n ,1 ,1 SPECIES. Mandible, 



avicularium dmerenciates it irom all the other x 85, of oral avicula- 

 known species. ^'um with two bundles 



mi nr , 7 7,- 111 , or MUSCULAR FIBERS 



Ihe genus Metrarabaotos is much developed 

 in the American Miocene and Pliocene. We have described sev- 

 eral very beautiful and vigorous species, but in which the fronds 

 are always free and bilamellar. 



The discovery of a recent well-developed species of this genus, much 

 developed on both sides of the Atlantic during the long geologic 

 periods, is very fortunate. When it is m^ore studied, the paleontolo- 

 gist will understand better the life conditions of the ancient seas. 



The genus Metrarabdotos is not really an equatorial genus. It lives 

 in the vicinity of the Tropics but it does not go beyond this area. 

 Occurrence. — Albatross Station D. 2363, east of Yucatan; 22° 07' 

 30" N.; 87° 06' 00'' W.; 21 fms.; white rock coral. 

 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. 

 Coty pes. —Cat. No. 7556, U.S.N.M. 

 58513—28 9 



