18'J7J MICROSCOPICAL JOURNAL. 23 



Dissecting in the same way the bind limb, determine 

 its various bones. Tin-roii^ i\ pc/vic gird/e attaching the 

 limb to the body ; this is directly articulated with the 

 spinal column, the point of attachment being on the sides 

 of the sacrujn. There is a cavity acetabulum into 

 which the upper limb bone of the leg fastens, formed by 

 three bones passing : one dorsally i\\^.iliuui\ a second 

 ventrally and in front, i\\e, pubis \ and a tliird \entrally 

 -and behind the ischium^ all three meet in the acetabulum. 

 The two ventral bones meet in the mid- ventral line and 

 compose an arch, the |)ubic arch, between which and the 

 back-bone the rectum and the uro-genital organs pass to 

 reach the cloaca. 



The/t*/;mr is the single bone of the upper limb thigh. In 

 the cms there are two bones, tibia, ^vi^ fibula\ they are of 

 the same size; the outer is the fibula; there ^v^.five digits, 

 locate and count their bones; examine the tarsus, it has 

 the same comj)Osition as the carpus, i. e. a proximal row, 

 tibiale, intermedium Siudi fibular e, centrale and distal tarsalia 

 I, 2, 3, 4, and 5. 



15. The Bones OF THE Skull. -TheskuUof thesalaman- 

 deris somewhat small for study of the bones and that of 

 a large frog is much the same and should be used in its 

 «tead if obtainable. The brain case is enclosed below 

 by cartilage, sphcu-ethmoid, which in the higher verte- 

 brates ossifies in two parts : the 'phenoid bone behind 

 and the ethmoid bone in front. Dorsally, tlie brain is 

 covered by the frontal bones in front and the parietal 

 bone.s behind. Below the sphen-ethmoid cartilage is a 

 dagger shaped para-sphenoid bone (not found where the 

 sphenoid and ethmoid are ossified). At the hinder end 

 of the brain-case the nervous tissue emerges through an 

 opening i\ie foramen-magnum \ this is i\iQ occipital region 

 of the skull but remains cartilaginous in amphibia except 

 where it articulates with the spinal column, here bones 



