BIOLOGICAL STL I 'IKS ON CORVMORPHA. 



III. 



287 



Aa tin- fir-t evidence in this direct inn I may refer at once t<> 

 certain I'--haped figure- formed from hcteromorphic segment- 1 >y 

 tin- attaclnncnt !" tin- latter to the bottom of tin- a(iiariuni di-h 

 by mean- of adhc-i\e ectoderm developed mi one -ide of the 

 column. Sin h a case is shown in Fig. lo, \\hich rcpre-ent- the 

 condition of a M _iin nt sixteen days after it^ remo\al fnnn the 

 di-ial hall" "I a i ilunin. A constriction define- the al>ral limits 

 1. 1 the n-^eneratinv; polyps. Frustules are pre-ent in two 



10. 



ri'iii:hl\- |ir<|mrti"iial in numbers to the >f the |>.l\|)s to 



which they belong, and situated in the p"-iti'n nnrmall\ nccupieil 

 l'\ I'rii-tule- ill the adult. The smaller p"I> p appn>ache- nmre 

 rl-el\ tn the proportions of the larva. < >n the lnlli\\ in^ <la> , 

 thi- process <>t li imi had been n'mpleted. pn>l.ably 1>\ rupture, 

 althi'ti.uh the pn-ximal end- uf the t\\p plvp- were then n>uudrd 

 and -month \\ithuut trace- nl -uch a p' 



Throiisji m\ failure, after repeated attempt-, to obtain many 

 Cases "f li ii.n nf thi- -<>rt, 1 found that a neces-ary ek-ment in 

 the (iroce was the adheii-nce of the hctcromorphic piece to the 



