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latter cell, in which the yellow granular bodies or sarcoblasts 
(e) are imbedded. 
Fifthly, (/), radiating and branched filaments, and in fully 
formed specimens, a clearly defined pellicle (g) upon the 
surface of the plastic granular material, thus including the 
sarcoblasts. The pellicle here spoken of may possibly corre- 
spond with the tubulated or fenestrated membrane forming 
the nidus of siliceous deposit in Collosphaera, though we find 
it coexisting with a zone of simple or compound spicules in 
many examples of Sphserozoum, while such spicules never 
coexist with the siliceous capsules of Collosphaera. In other 
forms of Protozoa, however, both siliceous capsules and radi- 
ating spicules are present. 
Fig 3 represents a specimen of Collosphaera of the natural 
size. 
Fig. 4 gives the analysis of one of the puncta of Fig. 3, 
highly magnified, and taking the parts from without inwards. 
( a ) A perfect punctum. 
( b ) The fenestrated capsule. 
(c) Animal cell-membrane surrounded by the yellow sarco- 
blasts. 
(. d ) Purple granular and crystalline matter contained 
within the last-mentioned cell. 
( e ) Transparent, highly refracting, spherical globule, im- 
bedded in the granular and crystalline matter, but, as also in 
the case of Spluerozoum, without distinct cell-membrane. 
Fig. 5. Another example of Sphserozoum, natural size. 
Fig. 6. The same considerably magnified to show the 
superficial distribution of the puncta between the central 
vacuolated substance and the gelatinous test. 
Thalassicolla nucleata. 
Fig. 7. Thalassicotla nucleata, natural size, with its trans- 
parent test and dark central spot. 
Fig. 8. The same as seen with a low power, and exhibiting 
the following parts, from without inwards : 
(a) The test. 
(. b ) The vacuolated substance situated between the test and 
the nucleus. 
(c) The sarcoblasts scattered amongst the roots of ( d ) the 
branched fibrous bands arising from (e) the external mem- 
brane of the central body, and here, like it, invested with 
black pigment granules. 1 
1 Any cyclosis so called occurring amongst these granules 1ms always 
appeared to me to be simple molecular motion, as in the choroid cells of the 
ox, &c. 
