504 



PROCEEDINOS OF THE NATIONAL MUSEUM. 



VOL. 39. 



SUBDIVISIONS OF CORYNOTRYPA. 



Three fairly distinct subdivisions of Corynotrypa may be recog- 

 nized, with, however, one or more intermediate species connecting 

 them. These, from their most characteristic species, may be known 

 as (1) the C. delicatula section, with long, exceedingly slender zooecia 

 enlarging very slowly and always remaining quite narrow at the 

 apertural portion; (2) the C. injlata section, in which the zooecia 

 enlarge rapidly after the slender, proximal stage is passed; and (3) 

 the C. dissimilis section, with broad, stout, little constricted zooecia 

 and often distinguished in addition by a surface ornamentation of 

 transverse lines. At least two quite dissimilar species, C. schucherti 

 and C. canadensis, are known, connecting the second and third 

 sections, while another well-marked form, C. harheri, appears to be 

 intermediate between sections 1 and 2. Merely for convenience of 

 classification, the difference in the angle of divergence of the aper- 

 tural portion of each zooecium is selected as the most distinctive char- 

 acter of the first and second sections. According to this scheme, 

 the species of Corynotrypa are distributed among these sections as 

 follows : 



CORYNOTRYPA DELICATULA SECTION. 



Angle of divergence small, proximal constriction well marked, 

 aperture constricted and with peristome. 



Species. 



Geologic range. 



C. delicatula (James) 



C. barberi, new species 



C. elorigala (Vine) 



C. nitida, new species 



C. tenuichorda (Ulrich and Bassler)<J. 



Ordovician and early Silurian. 



Do. 

 Silurian. 

 Devonian. 

 Cretaceous. 



a Several of the Cretaceous species of Stomatopora,&guied by d' Orbigny in the fifth volume of Paleontologie 

 Francaise, appear to have the characters of Corynotrypa, but in view of that author's diagrammatic and 

 frequently incorrect illustrations I have hesitated to refer them to the genus without a study of actual 

 specimens. 



CORYNOTRYPA IN FLAT A SECTION. 



Angle of divergence great, proximal constriction well marked, 

 aperture constricted and with peristome. 



Species. 



Angle of 

 divergence. 



Geologic range. 



C.infiata(na.\\) 



C. abrupta, new species. 

 C. curta, new species. . . 

 C. medialis, new species 



C. turgida (Ulrich) 



C. devonidb ( Oehlert) . . . 

 C.smithi (Phillips) 



40" 

 50° 

 70° 

 50° 

 70° 

 40° 

 40° 



Ordovician and early Silurian. 

 Earlv Silurian. 



Do. 



Do. 



Do. 

 Devonian. 

 Jurassic. 



