SUBJECT INDEX — MORPHOLOGICAL SECTION 



509 



Likewise references to certain structures de- 

 rived from the epidermis will be found else- 

 wliere, such as Phosphorescent organs unde:- 

 Lummosity, and Poison glands under Poisonous 

 fishes. 



The integument in fishes, as in all 

 vertebrates, consists of two layers, an 

 outer epidermis (Oberhaut) consisting of 

 the modified ectoderm, and an inner 

 dermis or corium (Cutis vera, Lederhaut) 

 composed of the outer or superficial layer 

 of the mesenchyme which is modified 

 mesoderm. 



The dermis in fishes is tliin and presents few 

 distinctive features. It has in consequence not 

 been the subject of extensive study. While 

 many of the following references include the 

 structure of the dermis, in general they refer 

 chiefly to the epidermis. 



Skin in general 



Miscellaneous papers on the skin of 

 Telcosts. Batelli, A. 1880.1; Leydig, F. 

 1851.1; Rathke, M. H. 1847.1. 



Papers relating to the structure of the 

 skin in the following Teleosts. — Murmna. 

 Clark, A. 1849.1. — Malapterurus. 

 Fritsch, G. T. 18S6.1. —Cyprinus. 

 Grunelius, A. 1913.1. — Lophius. Guitel, 

 F. 1890.2. — Cyclopterus. Hase, A. 

 1911.2. — Xiphias. Nardo, G. D. 

 1S41.2. — Salmo. Sacchi, M. 1887.1. — 

 Orthagoriscus. Turner, W. 1862.1. — 

 Synodontis. Vaillant, L. L. & Pettit, A. 

 1898.1. — Ameiurus. Wright, R. R. 

 1884.1. 



In the blind fish Typhlogobius, there is 

 " a highly abnormal development of blood- 

 vessels in the sub-epidermal portion of the 

 integument " obscuring the pigment layer 

 and giving the living fish a pink color. 

 This condition is presumably for the pur- 

 pose of cutaneous respiration. Ritter, W. 

 E. 1893.1. 



No true metamerism is shown in the skin, 

 such resemblances ■ are due to muscular 

 stresses. Grosser, O. 1905.1. 



Transplantation of patches of skin from 

 the uncolored ventral surface to the colored 

 dorsal surface and vice versa in Nejnachilus 

 show no changes in color of the transplanted 

 area until later immigration of chromato- 

 phores from surrounding areas and re- 

 sorption takes place. S6cerov, S. 1912.1. 



The skin of Anguilla, like other glandular 

 structures, undergoes an excitatory varia- 

 tion as a result of electrical, thermic, and 

 mechanical stimulation. Reid, E. "W. 

 1894.2; Reid, E. W. & Tolputt, A. G. 

 1894.4. 



Cutaneous sensor; papillae 



In the blind fishes (Amblyopsidos) , the 

 lack of eyes is compensated by the great de- 

 velopment, especially on the head, of the 

 cutaneous sensory papillce, "A'Eigenmann, 

 C. H. 1909.2. 



Although possessing eyes, the Gobiidce 

 likewise possess an extraordinary develop- 

 ment of such cutaneous papillm, whose 

 arrangement is said by Sanzo to be of 

 diagnostic value. ■A'Sanzo, L. 1911.1; 

 Winther, G. P. 1874.4. 



Xvrve Icniiiiiiilions in the epidermis. 

 Fusari, R. IDUl.l, 1907.1; Jobcrt, C. & 

 Grandey, - 1870.1; -A-Mcrkel, F. ISSO.l; 

 Rctzius, M. G. 1892.1, .5; Scholer, E. 

 ISS.5.1; Schulze, F. E. 1892.1. 



For the epidermal sense organs (Hatit- 

 sinnesorgane) , see End organs under 

 Senses and sense organs. 



THE EPIDERMIS 



The epidermis consists of two layers, a lower 

 thick layer of actively dividing cells, the stratum 

 of Malphigi and an outer layer of protective 

 cells, the stratum corneum, which to replace 

 wear is constantly renewed by division of the 

 cells in the lower or Malphigian layer. 



In various amphibians and reptiles this outer 

 layer (periderm) is periodically shed as a whole 

 but no such process occurs in fishes. 



_ The most comprehensive general treatise 

 (in German) on the epidermis, with a full 

 bibliography is *Studni6ka, F. K. 1909.1. 



Other older general treatises in German, 

 are *Leydig, F. 1879.1, and •Maurer, 

 F. 1895.1. 



Probably the best summary in English of 

 the literature on the epidermis of fishes is 

 given in •Reid, E. W. 1894.3. 



Glandular elements 



In correlation with their aquatic en- 

 vironment and in order to reduce surface 

 friction by the secretion of mucus or 

 " slime," the epidermis of fishes is gen- 

 erally rich in unicellular glandular struc- 

 tures. 



Leydig (F. 1851.1), according to Reid (E. W. 

 1894.3), first demonstrated the possibihty of a 

 secretory process in the fish skin by the descrip- 

 tion of specialized cells in the epidermis of 

 .some twelve genera of fishes. To these cells he 

 gave the general term " schleimzellen." Sub- 

 sequent research has shown that several varie- 

 ties were included under this general term. 



" Kolben " or club cells 

 ■The first of the elements subsequently de- 

 limited was the " Kolben " cell or " Kolbenfor- 

 mige Gebilde " of Max Schultze (1861.2) of the 

 epidermis in Petromyzon. By F. E. Schulze 

 (Add. 1867.1) the "kolben" cells were shown 

 to occur also in Tinea, Leuciscus, Cobitis, An- 

 guilla, Esox, and Silurus, and by Fritsch (G. T. 

 1886.1) in Malapterurus. These are the club 

 cells of authors (" clavate " cells of Wright, K. 

 R. 1884.1, p. 254). Schultze thought the " kol- 

 ben " cells to be of the nature of nervous end 

 organs and possibly contractile, because of cer- 

 tain appearances in polarized light, resembling 

 those of striated muscle fibre. Although this 

 view has been uplield by Pogojeff (L. 1889.1), 

 nearly all subsequent workers have agreed on 

 their secretory nature. Fcettinger (A. 1876.1) 

 followed their actual extrusion. The careful 

 experimental work of Reid (E. W. 1894.3) on 

 Anguilla, clearly demonstrates that the " club " 

 cells produce the fine granules in the slime and 

 also the threads, which are homologous with 

 and resemble the threads in the slime of Myxine 

 but are of finer texture. 



The most comprehensive treatise on the 

 " Kolben V cells, with a table showing the 

 fishes in which they occur or are absent is 

 •Oxner, M. 1905.1. 



" Becherzellen " or goblet cells 

 The second form of -secretory cell is the 

 " ' or Becherzell. Although known as the 



