14 IDMONEIDJ:. 



9. Idmoiiea gracillima, n.sp. (Plate YII. figs. 5, 6.) 



Zoarium dichotomous ; branches long and very slender; cells 

 usually in pairs on each side of the front of the branch, -Nvith inter- 

 mediate ones in front, the ontcr tubes the longest ; ooceeinm pyri- 

 form, prominent (like that of Crisia) ; surface smooth, dotted. 



Nab. Atlantic Ocean, 286-322 fathoms (H.M.S. 'Forciqnne'). 



Something like /. irrec/^nlaris in the disposition of the cells, but 

 much slenderer and more delicate. As the ooceciura of J. irregularis 

 is unknown, no conclusion can be drawn from its peculiar character 

 iu /. (jraciUiiiia, in which, unlike all other Idmonea, it is a distinct 

 pvriform vesicle, like that of a C'risia. 



Other recent s^x'cies noticed hi/ Anihors. 



10. Idmonea frondosa, Meneghini. 



Dichotomously branched, liranehes strongly divergent, rather 

 broad, tapering towards the end ; cells 6 in each series, long and 

 delicate, connate only at the base. 



Idmonea frondosa, 3Iencghini, I. c. p. 12 ; Ilvlkr, I. c. p. 120. 



Hah. Adriatic Sea. 



11. Idmonea gracilis, Meneghini. 



" Branches all directed to one sidej cells 5 in each series, the cen- 

 tral ones the longest." 



Idmouea gracilis, Meneyhini, I. c. p. 12; Heller, I. c. p. 120, 



Hah. Adriatic Sea. 



12. Idmonea serpula, Heller. 



" Dichotomously branched ; branches strongly divergent, rather 

 wide, lateral series closely approximated, alternate, each constituted 

 of 5-6 cells diminishing in length from the inner end of the series ; 

 the tM'O or three inner cells connate, the two or three outer usu- 

 ally free and curved outwards.'' 



Idmonea serpula, Heller, I. c. p. 120, pi. iii. figs. 8, 9. 

 ? Idmonea frondosa, Menegh. 



Hah. Adriatic Sea. 



This is very probably identical Mith /. frondosa, Menegh. 



13. Idmonea meneghinii, Heller. 



" Dichotomously branched ; branches moderately divergent, slender, 

 ?ubtriangular. lateral series approximated and oblique, alternate, 



