CONNECTIVE TISSUES. 27 
tissue cells, chromatophores, and partly to the presence of 
pigment granules in epithelium. The absence of pigmentation in 
animals belonging to species normally colored—albinism—is 
indicated by the white coloration of the hair and by the pink 
coloration of the eyes, the 
latter being due to the cir- Lerecertie 
cumstance that the _ blood- (BS Ge) 
vessels of the vascular tunic eo. ee 
are not concealed by pigment. eee eee: ——— - 
es 2 <a 
Se By 1 
B. Skeletal Tissues. Le iS) 
The skeletal tissues are 
solid forms of connective 
tissue which, on account of 
their more permanent shape, are better adapted to form a support 
for the body. They are of two kinds—cartilage and bone. 
Simple or hyaline cartilage (Fig. 8) is a semi-solid and some- 
what resilient material of a bluish or pearly coloration. It consists 
of a homogeneous matrix in which the cells are imbedded. The 
cells are distributed singly, 
Fic. 8. Hyaline cartilage: c.c., cartilage cell; 
1., lacuna; m., matrix. 


or more often in groups of SS 
¢ ae ae en eee | 
two to four, each group being i <  eee 
: : 0 Te IG ONS NG a eos 
contained in a small oval (Op Oe Raw 
; NS ee 
th rtil : | ER Mize = , 
space, the ca tilage lacuna ge hee k Coe ae huce 
The size of the spaces, and (Bk See ee Cea l 
eee . OF ne LL, 
also their distance apart, 1s ne AG Si 7s ie ht 
° pet Mie tt 0 eee a ag ae ey - Lh 9 
subject to great variation. IC j Qrx Se 
The addition of fibrous ele- ees =O --K lac. 
° aire bone Or — a = 
ments, usually of white fibres, EEE 
5 “ ——— = 
produces a modification 
Fic. 9. Intramembranous bone; froma ground 
known as fibrocartilage. section of the rabbit’s femur: c.l., circumferential 
A ‘ lamellae; h.c., Haversian canal; h.l., Haversian 
While fibro-cartilage occurs lamellae; i.1., interstitial lamellae; lac., lacuna. 
in certain situations, as in the 
symphysis of the pelvis, or in connection with the interarticular 
menisci and at the capsular margins of the joints. 
In the adult skeleton cartilage is present only in small amount. 
It forms the articular surfaces of joints, the ventral portions or 
