BY E. VON LENDENFELD, PH.D. 911 



8b (231). MONOSKLERA PUSILLA. Nov. Spec 

 Plate XL., Figs. 1, 2, 3. 



The Hydrorhiza forms a network of minute threads, -with 

 elongate meshes, which adheres closely to the Thalloms of 

 Macrocystis. The Hydrorhiza is thick- walled, and appears flattened 

 onthe side which is in contact with the seaweed. No such broad 

 extension, however, is formed as in Eucapella. The colour of the 

 Perisarc is light yellow. The Coenosark contains in the Entoderm 

 of the single specimen, which I obtained, and which was hardened 

 with chromic acid, numerous round cells, which take up Carmin 

 very freely ; they may, perhaps, be consiclei-ed as young stages of 

 ova. 



From this Hydrorhiza, erect and unbranched stems arise, which 

 attain a height of 10-15 mm. (Fig. 1.) They consist of a row of 

 Internodes, which ai*e wedge-shaped, and twice as broad at the 

 distal-end than at the proximal termination. These joints are fixed 

 to one another in this way that the narrow end of one is always 

 inverted into the broad and flat end of the preceding one laterally. 

 They are alternate, in as much as the third Internode grows 

 out from the left margin of the second ; the second out of the 

 right margin of the first. (Fig. 2 ) 



These Internodes consist of solid light yellow, and per- 

 fetly transparent Chitin. They are perforated by a cylin- 

 drical tube, which runs along the slanting side (Fig. 1 and 2), 

 and therefore appears regularly zig-zag-shaped. Between the 

 Internodes the tube is slightly constricted. 



From the upper end of the tube in each Internode (Fig. 3), a 

 process extends to the other side of the Internode, a small sac- 

 shaped excrescence of the cavity. This sac is in communication 

 with the cavity of the Hydrotheca, by means of a tube which 

 perforates the short peduncle of the Trophosome. The part of the 

 Internode which is solid, appears compressed, as a ridge con- 

 necting the main tube with the sac-shaped excrescence. The 

 Trophosomes are attached to the free part of the flat end of 

 the Internode. They are, therefore, alternate. (Fig. 2.) Genei'ally 



