AMERICAN KAULY TERTIARY BRYOXDA. Ml 



CONOPEUM LACROIXII Busk. 1852. 



Plate i::. fig. 9. 



ISL'd. Hnxtrii Iin-nii.rii Ariion.x, Explication sonnnaire ties planches de Polypes cie 1'Egypte 



et de l:i Syne, in Savigny's liosrnpiion de I'Essyple. Ilistoire Xatnrelle, pi. Ill, 



fig. 9. 

 1sri2. tfembrartipora lnrrni.rii r.rsu. Catalogue Marine Polyzoa. pi. 1. < 'heilostoniata, p. 



60, pi. 49 and pi. 304. fig. 1. 



1880. Mciiihriiniiiiira liirroi.rii HIM KS. Urilisli Marine Polyzoa. p. 129. pi. 17, figs. 5-8. 

 1900. Mcinhriinipora l<u-r<ii.rii UOHKRTSON. Papers from the Harriman Alaska Expedition, 



6, The Bryozoa. I'nic lings, Washington Academy Science, vol. 2. p. :'>2:t. 



1907. M<iliriinipor<i liiri-ni.rii CANU, Bryozoaires des terrains tertiaires des environs de 



Paris, Annales Paleontologie. vol. 1. \>. s. 

 1 ! is. \li-inbraiiiiiorri lni-riii.rii |{I>I:KI:TSOX, The Incrusting < Mu'llnsiiiniatous Bryozoa of the 



AYest Coast of Xorth Anicrira. I'niversity of California Publications, vol. 4, p. 261, 



pi. 14, fig. 5. 

 1 ;M is. Mi'iiiliriiiiiiiiini lurrni.rii CANT. Icoimu'raphie des Rrynxoaii-rs fi.ssiles di> 1' Argentine. 



Anales del Museo Nacional de Buenos Aires, vol. 17. p. 251, pi. 1, figs. 8, 9. 



1912. Miinliniinixiru Incrui.rii < ISI-.TRX. The Bryozoa of the Woods Hole Region. Bulletin 



Bureau Fisheries, vol. ?,0 (1910), p. 227. pi. 22, fig. 28. 



1913. Mciiiliniiiliinra Im-roi.rii CAXU. Ktude comparSe des Bryozoaires Helvetiens de 1'Egypte 



avec les Bryozoaires vivants de la Jlediterranee et de la Mer Rouge, Meraoires 

 Institnt Egyptien, vol. (1, p. ]9.i. pi. 1, figs. 5, 6. 



Not liifliifttrn liirroi.rii S.MITT, Floridan Bryoxoa. ]it. 2. Kongl. Svcnska \Vtrnskaps-Akade- 

 miens Handliugar. vol. 11, 1873, p. IS, pi. 4. figs. 85-88. 



The collections of American Tertiary hryozoa have yielded a number of ex- 

 amples of this interesting species which is widespread in both the recent and 

 ancient seas. 



. |A0=0.32-0.3G mm. . I Lz =0.36-0.40 mm. 



Measurements. Upesia 7 ^Hrv^ /ooecia,, 



17(9=0.12-0.22 mm. lte=0.2-t mm. 



It is not certain that the species described by Busk is that of Audouin. The 

 synonymy of Membranipora i-rfii'iiJiini ^jiven by Pergens in 18ST is absolutely fan- 

 tastical. To avoid confusion, Canu in 1007 restricted the synonomy to the species 

 described by Busk, including the living form and the few fossil specimens figured. 

 This restriction is still insufficient, as we believe that it is necessary to classify as 

 i iniopeum lacroixii only those specimens having interopesial cavities with distinct 

 walls and in which the average zooecial length does not exceed 0.40 mm. 



Vnriiif/oiix (ui(J tiffin if //'ft. This species presents two quite distinct aspects. 

 First, the zooecia have their mural rims separated by a deep furrow, and the 

 interopesial cavities are constant and provided with their own individual walls (see 

 figure by Miss Robertson). Second, the zooecia have their mural rims adjacent to 

 each other and their interopesial cavities are present or absent (as figured by 

 Osburn). 



In the living specimens llie-e two varialiun- occur on the same zoarium. but the 

 first appears less frequently. Different species may take the second aspect when 

 there are no interopesial cavities. This results in unusual difficulties in the. deter- 

 mination of the fossils and re<jiiiivs the greatest care for accurate n lei it i Heat ion. In 



