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AMERICAN MUSEUM OF NATURAE HISTORY 



Integument — Cont'd. 

 " Vesicula liinpida " of the intestinal epitlielium 

 by Henle as early as 1837, the " Beoherzellen " 

 were first adequately described by Schulze 

 (F. E. Add. 1867.1). The name " Becherzellen " 

 was first applied by this author in the " Cen- 

 tralbl. f. med. Wiss.," no. 11, 1866. These cells 

 occur in the epidermis of fishes and amphibians, 

 the intestinal epithelium of all vertebrates, and 

 in the "respiratory canal" of lung breathers. 

 The "Becherzellen" receive adequate treat- 

 ment (bibliographic, historical, etc.) by J. H. 

 List in the Arch. f. mikr. Anat., 1886, vol. 27, 

 pp. 481-588, 6 pis. 



According to the researches of Reid (E. W. 

 1894.3), the goblet cells supply the mucin and 

 after reaching the surface and discharging their 

 load, they are capable of undergoing regenera- 

 tion. 



The club cells, the goblet cells, and the or- 

 dinary epidermic cells, are descendants of the 

 palisade cells of the basal layer of the epidermis. 



Papers specifically relating to the goblet 

 cells are List, J. H. 1885.1-.3; Helly, K. 

 1905.1; Oedmannson,- 1863.1; Oeffinger, 

 H. 1867.1. 



Epidermis in general 



The following papers in general refer to 

 the histological structure of the epidermis 

 including the club and goblet cells and 

 other epidermal elements. 



Epidermis of Petromyzon. *FcEttinger, 

 A. 1876.1; •Kapelikin, V. 1897.1; 



Kolliker, R. A. 1860.6; Leuckart, C. G. 

 1856.1; Loewenthal, N. 1904.1; Ma- 

 renghi, G. 1903.1; MilUer, H. 1864.1,.2; 

 Pogojeff, L. 1889.1; Razzauti, A. 1911.1, 

 1912.1; Schultze, M.J. 1861.2; •Schulze, 

 F. E. 1863.1, Add. 1867.1; Studnieka, 

 F. K. 1909.1. 



Structure of the epidermis in Protop- 

 terus. Kolliker, R. A. 1860.1; Paulson, 

 O. M. 1865.1. 



Structure of the epidermis in the follow- 

 ing Teleosts. ■ — Salmo fario. Ebner, V. 

 1886.1. — Trachypterus. Kaschkarpff, 

 D. 1913.1. — Anguilla. Lengerken, H. 

 1913.1; Reid, E. W. 1894.2,.3. — 

 Teleosts. Nusbaum, J. & Kulczycki, W. 

 1906.1, .2. — Schizothorax and Capceta. 

 Pavlovskii, E. 1910.1, 1911.2. — Siluridae. 

 Rauther, M. 1907.1. 



Thread cells of MjTcine 

 The hagfish or " slime eel," Myxine gluti- 

 nosa, derived its specific name from its well 

 known habit of exuding enormous quantities of 

 mucus. According to Blomfield (J. E. 1882.1), 

 " two individuals thrown into a bucket of water 

 are capable of gelatinising the whole with their 

 secretion." 



This secretion, according to Reid (E. W, 

 1893.1), is derived from a double row of glands 

 (schleimsacke of Miiller), which are virtually 

 simple involutions of the skin (epidermal in- 

 pushings into the dermis), extending along the 

 belly of the animal from head to tail. Each 

 gland has a separate duct to the surface. _ These 

 structures were first described by Retzius (A. 

 J. 1824.1) but more accurately by Miiller (J. 

 1834,1, v). 



The secretion, before its dilution with water, 

 possesses a milky appearance due to the presence 

 of large numbers of cells, whose protoplasm has 

 been converted into a single complexly wound 

 thread which, after exudation, readily unwinds 

 and adds to the viscosity. 



These cells, called " Fadenkorper " by MuUer, 

 were independently termed "thread cells" by 

 Blomfield. They are apparently specialized 

 forms of the " Kolben " cells, described above, 

 and develop in the epidermal lining of the 

 gland. 



Papers relating to the epidermis of Myx- 

 ine with the thread cells, mucous glands, 

 etc. Blomfield, J. E. 1882.1; Kolliker, 

 R. A. 1860.6; and Retzius, M. G. 1905.1. 



Chemical examination of the mucous 

 secretions of Myxine shows granules pre- 

 senting most of the features of a mucin, but 

 which do not yield a body reducing Fehling's 

 solution. •Reid, E. W. 1893.1, 1894.1. 



Bdellostoma also encloses itself in a 

 transparent, gelatinous mass having the 

 consistency of thick egg albumen. Ayers, H. 

 1894.1. 



Comifications of epidermis 



In general the epidermis of fishes is 

 soft' and comifications of it are compara- 

 tivdy rare. 



Among such comifications are the 

 " pearl organs," small tubercles appearing 

 chiefly on the head of various Cyprinidw, 

 at breeding time. Leydig, F. 1892.2; 

 Reighard, J. 1903.2, 1904.1, 1910.2. 



Similar " contact organs " found on the 

 scales or fins of the males of some Pasciliidm 

 at the breeding season, are not purely epi- 

 dermal but possess an osseous or dermal 

 core. Newman, H. H. 1907.1, 1909.1. 



The " teeth " of the Cyclostomata {lam- 

 preys) are comified epidermal structures. 

 For references, see under Dentition. 



Deckplatte. In some embryonic Anamnia, 

 Petromyzon' and Amphibia, the outer layer of 

 ectoderm cells may, for a time, be ciliated.^ The 

 cUia however disappear upon the hardening of 

 the superficial protoplasm of the cells of the 

 stratum corneum to form a so-called cuticula. 

 By StudniCka (F. K. 1897.5) this striated cuti- 

 cular structure is termed " Deckplatte." 



In Lepadogaster, the epidermis of the 

 adhesive disk forms a thick cuticular plate. 

 Guitel, F. 1888.1; Studnieka, F. K. 

 1906.1, 1909.1. 



THE ARGENTEUM 



Underlying the dermis or corium of fishes is a 

 layer of connective tissue, the tela subcutanea. 



In many fishes, this layer contains numerous 

 crystals of guanin which form a refiecting layer 

 composing the argenteum which produces the 

 silvery coloration. 



According to Ewald and Krukenberg 

 (1883.1), quoted from Cunningham and Mac- 

 Munn (1893.1, p. 782), "the guanin is con- 

 tained in connective tissue cells, in some cases 

 in fine crystalhne plates as a lime compound 

 (guaninkalk) (Teleostei, Ganoidei, Cyclosto- 

 mata) , in others in the pure condition, and then 

 it is only dead white, and has no metallic lustre 

 (skin of Selachians)." The presence of guanin 

 likewise frequently gives a silvery appearance 

 to the peritoneum and the air bladder. " The 

 beautiful metallic appearance of the iris in fishes 

 is due to crystals of guanin." 



The discovery of the true nature of the 

 guanin is due to Barreswil (Add. 1861.1) who 

 upon making a chemical examination of the 

 " blanc d'ablette " or silvery substance ex- 

 tracted from the skin of the bleak (Alburnus) 

 and used in the manufacture of artificial pearls, 

 decided that this material was identical with 



