132 A Month on the Ti-ondhjein Fiord. 



inata, wliile those of Rhahdopleura have a3 yet evaded the 

 most careful search, and that of Cephalodiscus, from the habitat 

 of the animal, 245 fathoms in the Strait of Magellan, is not 

 likely soon to come under the section-knife of any naturalist, 

 unless one is forthcoming — even more ardent than those two 

 able men, Lankester and llarmer, who at different times have 

 spent their summer holidays on the Hardanger Fiord, seeking, 

 but in vain, for light on the developmental history of Rhah- 

 dopleura — who is willing to devote a year in the journey to 

 and search at Cejihalodiscas' s far distant and inliospitable 

 home. 



[To be continued. 1 



EXPLANATION OF THE PLATES. 



Plate VI. 

 All figures illustrate Electra pilosa, Linn. 



/■'///. 1. Var. (lentata, Ell. & Sol., an ordinary form of this variety. In the 

 zocecia fig-ured the oral aperture has fallen inwards and left a 

 gaping aperture, which does not therefore represent the proper 

 niouth-opeuing. 



Fry. 2. \&v. tenia's, Norman. 



JFi(/. 3. Var. ti/pica, Norman ; a condition of this variety incrusting a 

 round .stem in wiiich the ba^al sette are of great length. 



Fir/. 4. A single zoa'cium from the same specimen as the last, in which 

 two lateral .spines, as well as that at the base, are converted into 

 long setose appendages. 



Ft]/. 5. Var. tt/jnai, Norman. From the central portion of a specimen 

 coating a frond of Fucks strratus: at the lateral margins the 

 long seta^ are developetl, and a punctate portion of the base of 

 the cell is visible, while in the central part of the zoarium (that 

 is, on the side of the frond of the Fiwiis which it iucrusts) the 

 zooecia {as here figured) are oblong, and consist oidy of the 

 area and bounding walls, the ba.sal punctate portion being 

 AvhoUy absent ; the lateral spines short, stumpy, and strong, and 

 usually upright ; the basal spine is strong and also erect. 



Fir/. 6. Three zocecia from each of three rows running across the broad 

 part of a frond of mm: Jlustriformis from Batalden, showing au 

 unusual paiallel arrangement instead of the quiucuncial order 

 which usunllv prevails. 



Fir/. 7. \i\r. /ii/>pof/ioi/ormis, Norman; Floro, Noi-way. Tlie cells of the 

 nuiin stem in the part tiguiod are for some reason in an abnormal 

 condition, and constricted at the origin of the pinn;^. The 

 iigure is .-somewhat diagrammatic, because 1 have not seen the 

 pinuuhv ciinnnence so low down as on the lirst or second 

 zooicium; they nniy be expected about the tilth, but apparently 

 the only cause for tJiis is want of room ; but in tlie drawing for 

 a similar reason, " tca7tt of roam," the illustration of what 

 subsequently takes place at a greater distance from the main 

 stem in reality has been here given nearer the origin of the 

 piim;v.>. 



N.B. — The tiL'ures on the Plate are drawn to diiVerent degree* of enlarge- 

 ment. 



