ilO ERNEST WAR K EX. 



ectodenn of the host. On each side of the endoderm-tube 

 there may be noticed a chimp of large cells {gl. c.) containing 

 globules resembling those seen in the endoderm cells. 



The example of parasitism is interesting in that^ as far as I 

 am aware, it is unique, and it exhibits in a striking manner 

 the struggle of the host to squeeze out the parasite and shut 

 it off from its depredations. It also illustrates the economy 

 exei'cised by the parasite in the secretion of perisarc. AA'hile 

 within the body of the host it produces practically no peri- 

 sarc, and utilises the hydrotheca? of the host ; but when for 

 any reason the hydrotheca is too short, it may be lengthened 

 as in Text-fig. 2, B, D. Immediately on passing out to the 

 exterior a substantial perisarc is formed. The fact of being- 

 housed and partially fed by the host during the younger 

 stages in the growth of the parasite, must certainly be a 

 great advantage to the Laf oea, as it thereby esca23es some of 

 the dangers of this critical period. 



With reference to the specific characters of the Lafcjea 

 there is but little to state, since, as is so usual in specimens of 

 this genus, no gonangia were present. 



Hydrorhiza. — Creeping and apparently irregularly 

 branched. 



Diameter, when outside the host, O'lO mm. 

 Thickness of perisarc, 11 ^. 



Hydro caulus. — Represented by the short pedicels of the 

 hydrotheca^, smooth or slightly Avrinkled. 

 Diameter about 0'05 mm. 



Hydrothecfe. — Carried on short pedicels, and rather 

 sparingly scattered on the hydrorhiza when the parasite is 

 outside of the host. Cylindrical, margin not perceptibly 

 everted. 



Length, O'o9 mm.; breadth, 0'18 mm. 



Thickness of perisarc, 5 /a. There is a slight indication of 

 a diaphragm. 



Hydranth. — Cylindrical, with a crown of eight tentacles, 

 which are somewhat moniliform. Hypostome hemispherical. 

 The ectoderm of the polyp tends to be thin, while the endo- 



