14.0 QUARTERLY CHRONICLE. 
tion throughout, except at the middle, where there is an 
interval of =,),,th of an inch between them, or equal to 
three times the breadth of the neighbouring rings. 7. The 
sheaths elongating, carry out the ends of the capsules upon 
their extremities. 8. The hemispheres of the capsules dis- 
integrate into short, fusiform, curved, thread-like filaments. 
9. The sheath is fully formed, and the sporangial frustule 
appears within it. 10. The empty sheath presents a longi- 
tudinal dehiscent fissure, through which the sporangial 
frustule obtains its exit.” When boiled in nitric acid, 
the sheaths, as stated by Dr. Griffith, remained entire. 
Mr. Carter then adds some general remarks, and describes 
the conjugation in two other species, his observations 
being most excellently illustrated by careful drawings. He 
then adverts to certain points of controversy between himself 
and the late Professor Smith, and then discusses the nature 
of this process of conjugation. After carefully adducing 
his reasons, and giving due regard to opposing facts, he 
comes to the conclusion that, im all probability, the con- 
jugation of Diatomaceze may be looked upon in the same 
light as the similar process occurring in Rhizopoda. The 
parts and organs of the two groups he contends, are homolo- 
gous, and, finally, whilst he considers the nucleus in the 
Rhizopod Difflugia as contributing the sperm in the encysta- 
tion of two of these individuals (a process which he holds to 
be an act of true sexual reproduction), and some other part 
of the body as furnishing the germ-cells, so, in the conjugation 
of Diatomacez, he is inclined to regard the nucleus as fur- 
nishing sperm, and what he formerly described as the “ glair- 
cell” (a capsuled body, situated at each end of the frustule) 
as giving rise to the germ-cells. For a fuller exposition of his 
views, we must refer the reader to Mr. Carter’s very able paper. 
Further Observations on Raphides and other Crystals in 
Plants. By G. Guiitver, F.R.S. (Ann. and Mag. of 
Nat. Hist.,’ January, 1865.)—From time to time, Prof. Gul- 
liver publishes his notes of observations in search of raphides, 
in which he has varying success. 
Terustreminacee.—Spheraphides in leaves and young 
bark of Canelha. 
Vitacee.—Raphides and spheraphides, as in all plants 
examined of this order. 
Zygophyliacee.—Large four-sided prisms in Guaiacum 
officinalis, as in Quillaja and Tris, &e. 
Melastomacee, plenteous sphzeraphides in Melastoma, sp. 
Passifloracee.—Spheeraphides in two sp. Passiflora. 
