IDMONEA ATLANTICA. 461 



Iii their adult state the Idmo//c,c Fig. 23. 



are attached by a somewhat expanded 

 base, the surface of which is lineated 

 or striated ; but their earliest stage 

 is, I believe, identical with that of 

 Tkbulipora. The two conditions may 

 be readily observed in /. serpens, which 

 may be found in its adnate and re- 

 pent form with the primitive disk idmowa, early stage, 

 and the slender Stomatopora-like 



base, whilst in the suberect and radiate form, described 

 hereafter, it is attached by a slightly spreading crusta- 

 ceous base. 



The present genus has almost a world- wide range, and 

 is represented by numerous species. Many charming 

 forms occur in the Cretaceous deposits. 



IDMONEA ATLANTICA, E. Forbes. 

 Plate LXV. fig8. 1-4. 



IDHONKA ATLASTICA, Forbes, MSS. : Johnston, B. Z. ed. 2, 278, pi. ilviii. 



fig. 3: Gray, B.M. Bad. 141: Gosse, Mar. Zool. pt 2, 8, 



fig. 3 : Busk, Ann. N. H. ser. 2, rriii. 34, pi. i. fig. 6 a-e ; 



Quart. Journ. Micr. Sc. vi. 128, pi. xviii. fig. 5; Rep. Brit. 



AMCC. (1859), Trans. Sect. 146 (var. tenuis); B.M. Cat. iii. 



11, pi. ix. : Smitt (subgen.), loc. cit. 398 and 434, pi. iii. figs. 



6, 7, pi. iv. figs. 4-13 ; Flor. Bryoz. 6, pi. ii. figs. 7, 8 (slender 



form): Manzoni, Bryoz. d. Miocene d' Austria, pt. iii. 4, pL ii. 



fig. 6. 

 IDUOXEA RADIANB, V. Beneden, Bryoz. d. la Mer d. Nord, Bull. Brux. ivi. 



pt. 2, 646, pi. i. figs. 4-6. 

 ? IDMOXEA COROSOPUS, Dffranct, Diet. Sc. Nat. ixii. 565 : M.- Edwards, Recb., 



M6m. sur les Crisies &c. 23, pi. xii. fig. 3. 

 ?IDMOXEA AMGCSTATA, IfOrbigny, Pal. Fr. terr. cret. v. 731. 



Zourium erect, white, punctulate, irregularly branched 

 dichotomously ; branches much in the same plane, 



2a 2 



