of the Jurassic Bryozoa. 225 



dicliotomously or irregularly, and sometimes anastomose into 

 a reticular web. The peristome is flush or slightly raised. 

 Zooecia tubular or subpyritonn. 



Type species: S. dichotonia (Lamouroux). 



1. Stomatopora dichotoma (Larax.). 



Alecto dichotoma, Lamouroux, 1821, Exp. m^th. Polyp, p. 84, pi. Ixxxi.. 



figs. 12-14. 

 Stomatopora dichotoma, Bronn, 1825, Pflanzenth. pp. 27, 43, pi. vii. 



fig. 3. 

 Aulopora dichotoma, Goldfuss, 1831, Petref. Germ. Bd. i. p. 218, 



pi. Ixv. fig. 2(?non2«). 

 Stomatopora antiqua, Ilaime, 1854, M6m. See. g6ol. France, ser. 2, 



t. V. p. 162, pi. vi. fig. 7. 

 Stomatopora Haimei, Terq. & Piette, 1865, ibid. ser. 2, t. viii. p. 124, 



p]. xiv. figs. 29, 30. 

 Stomatojwra dilataiis inontlivaltiformis, Vine, 1883, Rep. Brit. Assoc. 



1882, p. 251. 

 Stomatojwra Terquemi, Haime, 1854, op. cit. p. 164, pi. vi. tig. 4. 

 Stomatopora Waltoni (nou Haime), Vine, 1884, Quart. Journ. Geol. 



Soc. vol. xl. p. 787. 

 Stomatopora spirata, Walford, 1889, ibid. vol. xlv. p. 564, pi. xviii. 



fig. 6. 

 Sto7natoporar)orrecta,y^?i\ioxd., 1889, ibid. vol. xlv. p. 565, pi. xviii. 



figs. 7, 8. 



Diagnosis. — Zoarium typically forming a loose irregular 

 network ; the lines radiate from the centre and repeatedly 

 branch dichotomously. Eight or ten zooecia may occur 

 between two points of bifurcation. Such series are often 

 curved (var. sjnrata, Waif.). Young forms consist of a 

 single line, which may at first branch very sparingly (var. 

 porrecta^ Waif.). Crowded growths occur. 



Zooecia regularly cylindrical. 



reristomes well raised, varying in height from half to one 

 and a half times the diameter ot the zooecia. Surface punc- 

 tulate and transversely wrinkled. The wrinkling is best 

 seen in young zooecia. The normal zooecia vary in length 

 from one and a half to three times the diameter. 



Ooeaa small ; appear as small hemisplierical tubercles ; 

 diameter about half that of the zooecia ; punctulate. 



Distribution. — England : Lower Lias to Cornbrash. 

 Foreign : Sinemurian to Kimeridgian ; France and Germany. 



2. Stomatoijora dichotomoides (d'Orb.). 



Alecto dichotomoides, d'Orbigny, 1849, Prod. Pal. t. i. p. 288. 

 Stomatopora dichotomoides, d'Orbigny, 1852, Pal. Franc;., Terr. Orel 



t. v. p. 834. 

 Stomatopora Bouchardi, Haime, 1854, Mem. Soc, g^ol. France, ser. 2, 



t. V. p. 164, pi. vi. fig. 6. 



