IDMONEA ATLANTICA. 451 



In their adult state the Idmonea 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 

 TubuUpora. The two conditions may- 

 be readily observed in 7. serpens, which 

 may be found in its adnate and re- 

 pent form with the primitive disk /^,„on.«, early stage. 

 and the slender Siomatopora-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. figs. 1-4. 



Idmonea Atlantica, Forbes, MSS. : Johnston, B. Z. ed. 2, 278, pi. xlviii. 



fig. 3 : Grrai/, B.M. Eacl. 141 : Gosse, Mar. Zool. pt. 2, 8, 



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



Quart. Journ. Micr. So. vi. 128, pi. xviii. fig. 5 ; Eep. Brit. 



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



11, pi. ix. : Sinitt (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 dAustria, pt. iii. 4, pi. ii. 



fig. 6. 

 Idmonea radians, V. Beneden, Bryoz. d. la Mer d. Nord, Bull. Briix. xyi. 



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

 ? Idmonea coronopus, Dcfmnce, Diet. Sc. Nat. xxii. .565 ; M.-Edwards, Eech., 



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

 ? Idmonea angustata, IfOrhigny, Pal. Fr. terr. cret. v. 731. 



Zoarium erect, white, punctulate, irregularly branched 

 dichotomously ; branches much in the same plane, 



2g 2 



