Zoological Society. 203 
excepting even the Camelide. It is only during the earlier period of 
intra-uterine life that the corpuscle of mammals has a nucleus corre- 
sponding to the permanent one in the corpuscle of lower animals. In 
birds, the nucleus, when exposed by a weak acid, is commonly longer 
in proportion to its breadth than the envelope; but there are some 
exceptions, and the nucleus becomes globular or nearly so when in 
contact with water. In the blood-corpuscle of mammals the central 
spot, so often mistaken for a nucleus, is not visible in the best focus 
and light; then if the object-glass be so slightly removed from the 
corpuscles as not to destroy their clear contour, a dark spot appears 
in their centre; if the glass be next so far moved towards the corpus- 
cles as to place them slightly within the focus, the dark spot will be- 
come bright ; and when altogether invisible in a bright light, the spot 
may be instantly brought into view simply by diminishing the light. 
Note.—The following measurements are all in vulgar fractions of 
an English inch; but for the sake of convenience, the numerator is 
omitted throughout, as it is invariably 1, and the denominators only 
are printed. ‘The measurements of the blood-discs are given as they 
lie flat, unless when a T indicates a measurement of their thickness. 
By L.D. the long diameter and by S.D. the short diameter is de- 
noted. The measurements refer exclusively to average sizes. The 
nuclei were measured after exposing them by the action of dilute 
acetic acid on the envelopes. 
MAMMALIA. 
-|Homo ....... Pavscceus Ribas wasvoouhs BIOO jAteles ater .......csccccccscscaraes 3602 
T...|12400 ||——- Belzebuth  .............00045 3589 
et Com, anaes, Cebus Apella sasdicwse okgawenahen 3467 
pepe RUPOCAINUON. > vate cveccensanltcs 3454 
Simia Troglodytes .......+.. seses| D412 |\Callithrix sciureus .........00000. 3713 
Pithecus Satyrus .........-.seeeees 3383 |/Jacchus vulgaris ........sseeseees 3624 
Hylobates Hoolock .........00.+++ 3368 |/Midas Rosalia ....... bisieuebareuas 3510 
—— leucogenys ......... aie 3425 
—— Rafflesii ..........c eee ee eee 3539 L 
Semnopithecus Maurus .........! 3515 shies Cabal 
Cercopithecus Mona waea sae weeks 3468 Lemur albifrons Ceoeeesseeee @eeree 3976 
meee MeN occa cccoes 3342 Catia ceececssesesereesseeeees 3892 
——— FUNIPINOBUS ......00....00000- | 3530 || Anjuanensis ............... 4003 
BN evi ces sae} <oessssso08 3395 MIGTIFTONS — ....sesseesseeeees 4440 
bee PMIMOREN © <00.525..dncescesescs 3578 ||Loris tardigradus ..........s.+006+. 3691 
—— pygerythrus ~............... 3401 BOSC icici Se 3461 
—— Petaurista .........sercesees 3478 
—— griseo-viridis ............+6. 3429 CHEIROPTERA, 
—— AMthiops ......ceceeesees veee-| D404 arts] . : 
Macacus radiatus ............eeees 3563 Vesper alin mirtinus +. sneer: 4175 
Burs ree 3429 OCs. a o.s. cesses scceneins 4404 
dine Se ee 4324 
Be Eynomolgus «....c:-...as0es0s 3499 Plecotus auritus ........+.00. seees| 4465 
———  Silenus os. seseeeeceeeerecees 3430 
J-——— NEMESETINUS cee eeeeseeeeees 3493 possess ones 
——  SylVANUS ......... es eeee eee eee 3338 |\Talpa Europaa .........cc0c00.e. 4747 
i—— melanotus ...... sees vcmuneae 3389 |\Erinaceus Europeus ............ 4085 
Cynocephalus Anubis ............ 3461 |Sorex tetragonurus ...........066: 4571 
| Teucopheens ......... 2.200.005 3555 || 
PLANTIGRADA. 
Simia PLaTyRRuINI. ‘Meles VOIGEEIN . <0 ssceracavdenb ens 3940 
Ateles subpentadactylus ......... 3620 |,Arctonyx collaris .,........ sovcvees| DOOD 
