8i 



another between the two internodes, and a third at the distal end of the second internode (z. 2 ), 

 after which the main rootlet is continued as a delicate thread. The distal internode gives off a 

 pair of opposite rootlets, which do not branch ; each being separated from the internode by a 

 diaphragm. The proximal internode similarly gives off two opposite branches, but each of these 

 at once becomes a short internode (/. z'. 1 ), which gives off two dichotomously arranged branches. 

 One of these, in each case, continues as an unbranched rootlet, while the other forms a new 

 internode (/. ï. 2 ), bevond which the branch is continued as a rootlet, while a pair of lateral 

 rootlets are given off on either side, or one such rootlet on one side. This description may be 

 summarised by saying that each branching of the rootlets is preceded by the formation of a 

 short internode, which is separated from each rootlet with which it is in communication by a 

 diaphragm. Some of these internodes give rise, further, to erect sterns, as shown in fig. 5. On 

 reversing the slide the base of an erect stem (s) may be seen to originate from the internode i}. 

 The rootlet marked r? proceeds for some distance without branching, and then forms a new 

 internode from which another erect stem arises. 



The total length of the stem shown in fig. 5, including the part which has been omitted 

 in the drawing, is 12.35 rnm., or nearly halfan inch. The longest zooecium shown in the same 

 figure is 750 a in length: while the longer zooecium of fig. 3 is 740 f*, long and 70 u. in greatest 

 breadth. The proximal stern-segment of fig. 5 is 2 1 60 u. long ; while in the middle of the stem 

 the segments average about 240 \i. in length and about 40 u. in breadth. The larger rootlets 

 are 32 0. broad. The diameter of the circular or oval bracket-like supports of the zooecia is 

 about 20 — 22 u.. 



The present species is strikingly different from M. gracilis, the genotype of Mimosella. 

 Some of the most noteworthy respects in which it differs from that species are : — the jointed 

 character of the erect sterns, the greater relative length of the zooecia and the presence of 

 four zooecia instead of two on each of the stem-segments. 



Mr Waters, who found this species simultaneously with myself, has been kind enough to 

 suppress the name which he had given to it in favour of the one I had proposed to introducé. 



2. Mimosella verticillata Heller. (PI. VII, figs 8 — 10). 



Valkeria verticillata Heller, 1867, "Bry. adriat. Meeres", Verh. k. k. zool.-bot. Ges. Wien, 



XVII, p. 129, PI. VI, fig. 4. 

 Hippuraria verticillata Hincks, 1887, u Pol. Adriat.", Ann. Mag. Nat. Hist. (5) XIX, p. 311, 



PI. IX, fig. 8, Sa. 

 Hippuraria verticillata Carus, 1889, "Prodr. Faun. Med.", II, p. 51. 

 Hippuraria verticillata Ostrooumoff, 1896, u Otchet Exp. 'Selianik' "', Buil. Ac. Imp. St-Pétersb. 



(5) V, p. 78 (Sea of Marmara). 

 Lagenella nutans Joliet, 1877, "Contr. hist. Bry. cótes de France", Arch. Zool. Exp. VI, 



p. 293, sep. 101 (Roscoff). 

 Valkeria nutans ) Joliet, 1888, "Ét. Pyrosoma, suivies de Rech. Bry. Roscoff et Menton" 

 Walkeria nutans S (Paris), p. 106, PI. V, fig. 4. 



139. D. Stat. 164. i°42'.5 S„ I30°47.5E., 32 Metres; sand, small stones and shells. 



39. C. Stat. Jj. Borneo Bank. 3°27'S., II7°36'E., 59 Metres ; fine grey coral-sand. 



(?sp.) 130. F. Stat. 164. i°42'.5 S., I30°47'.5 E., 32 Metres; sand, small stones and shells. 



Sr 



SIBOGA-F.XPEDIT1E XXVIII ö. I I 



