TURNER ON THE INTEGUMENT OF THE SHORT SUN-FISH. 187 



radiated, aspect, which has recently beeu described by many observers, 

 in connection with tlie corpuscles of the connective tissue generally. 

 For this purpose I subjected, to repeated observation, portions, not 

 only of the fresh skin, but also sections which had been hardened in 

 spirit, or chromic acid, without being able to convince myself that 

 such stellate connective-tissue corpuscles existed in this cutis.* 

 Passing through the cutis from its deep to the tubercle-covered 

 surface many nerve fibres were seen. In slices of the skin, which 

 had been previously steeped in chromic acid, and then slightly acted 

 on by caustic potash, the nerve fibres appeared, as they approached 

 the deep surface of the tubercles, to present indications of a net-work- 

 like arrangement beneath the tubercles, bu.t not entering in them. 



When the free surface of the integument was examined it was 

 seen to consist of a multitude of tubercular plates, large enough to be 

 distinguished by the naked eye, but requii'ing for their due examination 

 the use of a compound microscope. These tubercles were polygonal 

 in shape, irregularly serrated at their margins, by which serratures they 

 were connected together. (Fig. 5.) A short firm spine projected from 

 the centre of each tubercular plate. In some eases the spine was 

 acuminated at its free extremity, but more generally it was an 

 irregular ridge-Hke projection, widening out at the base and 

 strengthened laterally by buttresses. These spines gave to the 

 surface of the skin a shagreen-like aspect. A granular pigment 

 was scattered over the surface of many of the plates. In some cases 

 it wa.s collected into stellate, at others into rounded masses, and at 

 others it existed as free scattered granules. It gave to the tubercles a 

 brownish colour, or metallic lustre. It was never found on the 

 apices of the spines, although it frequently extended for some 

 distance up their sides. The tubercles which did not possess any 

 pigment, had a dull white appearance. 



Vertical sections through the tubercles and their spines, enabled 

 one to obtain a clearer conception, not only of their structure, but 

 of their relation to the subjacent cutis. (Fig. 6.) The tubercles 

 rested by their deep aspect on the fibrous cutis, with which they 

 were very closely united. The outline of this portion of the cutis 

 was unbroken and continuous, not at all times straiglit but slightly 

 undulating, and occasionally presenting short digitiform elevations, 

 which might, although did not necessarily, correspond to the position 

 of the spines of the tubercles. Tlie tubercles themselves consisted of 

 two parts, which possessed distinctive microscopic characters, a 

 superficial cuticular and a deeper hard portion, both of which 

 differed structui-ally and chemically from the subjacent fibrous cutis. 



* It is important, therefore, in discussing the presence of corpuscles in con- 

 nective tissue, to keep in mind, tliat they may exist in very large numbers in this 

 texture, a.« in the skin now under consideration, without possessing a radiated and 

 anastomosing arrangement. 



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