422 Prof. M'Intosli on the 



compact aiid granular than the rest) are directed from each 

 side downward and inward, then outward toward the narrow 

 part under the external muscle. The lateral division has the 

 form of a lanceolate process on each side, the wide hase 

 abiittinji on the convex margin of the muscular compartment, 

 from which a chitinous plate proceeds outward along the 

 central line. The hypodermic tissue is lax at the basal or 

 Avide portion, and becomes more granular toward the free 

 margin in the preparations. In transverse vertical section 

 the soft connective-tissue fibres extend from the central 

 chitinous plate upward and outward dorsally and downward 

 and outward ventrally, the whole having the aspect of a leaf 

 with its midrib and veins. At the external margin a fan-like 

 arrangement of the fibres occurs. In vertical longitudinal 

 sections a similar appearance is found, though in this case 

 the leaf is almost linear. No trace of capillaries occurs in 

 the lateral or other hypoderm of the snout. 



Proceeding backward, the ventral hypodermic tissue 

 increases in bulk, and its structure becomes more distinctly 

 fibrous, and by-and-by it passes upward so as to separate the 

 median muscular spaces, as in front. In the large area 

 formed between the latter spaces the fibres of the hypoderm 

 follow definite courses. Dorsally they sweep from the 

 cuticular margin downward and outward to the inner mus- 

 cular compartment, and a few of the inner fibres pass to the 

 chamber for the blood-vessels beneath. Ventrally they are 

 directed from the latter and the chitinous process externally, 

 downward and inward to the cuticle. Such fibres would aid 

 in retaining the muscular chambers in position during the 

 varied movements of the snout and give firmness to the 

 region. Still increasing in extent, the ventral hypoderm 

 then presents a small oblong area above the cuticle, in the 

 median line. This is the precursor of the great transverse 

 space immediately behind. Above the latter space the hypo- 

 derm is vertically streaked by somewhat isolated bands of 

 fibres, and numerous granular cells occur all over, especially 

 in the more opaque central region superiorly. When the 

 latter has reached its full development the large dorsal area 

 with its dense covering of cuticle is divisible into two parts — 

 an upper cellulo-granular and an inferior fibro-granular 

 region — stretching from side to side between the remnants 

 of the central longitudinal muscle. The fibres are chiefly 

 transverse in direction, though some (apparently pertaining 

 to the vertical series previously mentioned) pass at right 

 angles to these from above downward to the roof of the 

 space. The ventral hypoderm is now much more lax and 



