8 PROCEEDINGS OF THE NATIONAL, MUSEUM. vol. «1. 



This family is characterized by the size of its larva which, although 

 anknown, is established by the unusual size of the oeciostome. 

 Although similar to the Oncousoeciidae in the arrangement of the 

 ovicell parallel with the tubes, it differs in its formation before the 

 calcification of the near-by tubes. 



Genus MACROECIA Canu, 1918. 



1918. Macroccia Canu, Les ovicelles des bryozoaires cyclostomes, Bulletin 

 Soci6t6 Geologique de France, ser. 4, vol. 16, p. 328.— 1920. Canu and 

 Basslee, North American Early Tertiary Bryozoa, Bull. 106, U. S. 

 National Museum, p. 722. 



The ovicell is elongate, elliptical, very salient. The oeciostome is 

 not turned toward the bottom. 



Genotype. — Macroecia {Diastopora) lamellosa Michelin, 1846, 

 Jurassic. 



MACROECIA LAMELLOSA Michelin, 1846. 



1896. Diastopora lamellosa Geegoby, Catalogue of the Jurassic Bryozoa in 

 the British Museum, p. 126, fig. 35 (p. 17) pi. 7, fig. 3 (bibUography and 

 geologic distribution). 



1920. Ma-croecia lamellosa Canu and Bassleb, North American Early Ter 

 tiary Bryozoa, Bull. 106, U. S. National Museum, p. 723, fig. 235A-D, 

 F-I (Not fig. 235 E or 227 H^Atractosoecia edtvardsi Canu, 1913). 



The structure of this species is still little understood. In longi- 

 tudinal sections the tubes are short, enlarged at the middle, with 

 thick walls ; the gemmation is triparietal on the zooecia of the oppo- 

 site pseudolamella. In transverse section there is no basal lamella. 

 The tubes are polygonal, with thick walls, nonsymmetrically ar- 

 ranged on each side of the median axis. 



This structure in this species is remarkable and quite unexpected. 

 The fronds are not formed by lamellae approaching each other or 

 by the tubes developing from each side of a median lamella, but it 

 is a foliaceous structure. The tubes are not at the same height in 

 the transverse section and on the two zoarial faces; each tube of 

 one side serves as a support to a more elevated tube on the other 

 side. 



Gregory in 1896 has published a longitudinal section of a multi- 

 lamellar specimen. This same structure is here apparent; more- 

 over the exterior lamellae appear to have a basal lamella. The 

 transverse section in an analogous specimen figured by Haime, 1854, 

 indicates a median lamella. These two sections need confirmation, 

 for they do not seem to correspond. However, the dissymetrical 

 character of the sections is clearly apparent. 



Canu and Bassler in 1920 as noted in the synonymy above, included 

 a figure of Atractosoecia edwardsi Canu, 1913, in their illustrations 

 of this species. Further studies are still necessary upon this interest- 

 ing Jurassic bryozoan. 



