liEPOItT ON THE DEEP-SEA MEDUSAE. xxxi 



cathamrnalis," otherwise also " endodermal lamella," and " vascular plate"; comp. under 

 " Cathamma," §§ 100, 101). 



§ 48. Connective tissue ("tela connectiva"). The connective tissue (padding tissue or 

 supporting tissue), whose various modifications are included in the idea of the " con- 

 nectivum"), appears among the Medusae in two different principal forms, as supporting 

 plates without cells ("fulcra"), and as padding tissue containing cells (" maltha"). The 

 two forms correspond to different phylogenetic stages of development, as the cell-less 

 supporting plate or fulcral plate only represents a simple secretion of the epithelium, 

 which has no independent value as mesoderm ; we can only consider as mesoderm the 

 cellular filling tissue or malthar plate, by which cells are produced from the endoderm 

 and are divided by an intersubstance (" secreted tissue "). Both forms are produced 

 in general from the endoderm ; though both forms are also produced in a few isolated 

 places from the ectoderm. 



§ 49. Supporting tissue or cell-less connective tissue (" fulcrum," " tela fulcralis," 

 "lamina fulcralis"). Under this name we include all forms of the connective tissue which 

 do not contain cells, and are therefore merely structureless or fibrous secretions of the 

 epithelia. They appear in two principal forms, which, however, appear inseparably 

 connected by transitions, as thin elastic membranes and as thick gelatinous masses. The 

 thin elastic supporting membranes are found everywhere in the bodies of the Medusae as 

 the foundation of the epithelium, and especially of the endoderm, although strongly 

 developed supporting plates often appear also among the ectoderm at definite spots, e.g., 

 in the velum of the Craspedotas (PI. VI. figs. 13, 14, zv; PI. IX. fig. 7, zr) ; and in the 

 tentacles of many Acraspedae. The structureless fulcral lamellae are generally very thin but 

 very firm ; in transverse section, under strong magnifying power, they appear sometimes 

 simple, sometimes doubly contoured, usually strongly refractive. On account of then- 

 great elasticity, they are often of physiological importance as antagonists of the muscles 

 (e.g., as extensors of the tentacles and oral styles). This is also the case with the thick 

 cell-less gelatinous tissue, which is only distinguished from the thin elastic supporting 

 membranes by its more extensive, often very apparent volume of development. This 

 forms the principal mass of the gelatinous umbrella (and consequently of the whole 

 body) in the majority of the Craspedotae, as in this section the collosoma is usually 

 without cells, and appears as a structureless secretion of the endoderm ; it also forms 

 the principal body mass in part of the Acraspedae (e.g., Cubomedusse, Pelagidte, 

 Cyaneidas). The cell-less " fulcral gelatinous tissue," is, moreover, usually (or always?) 

 traversed by numerous elastic fibres, in the same way as the cellular "malthar gela- 

 tinous tissue." 



§ 50. Padding tissue or cellular connective tissue (" maltha," "rete malthare," "lamina 

 maltharis "). Under this name (for want of a better) we include all the different forms of 

 cellular connective tissue, in contradistinction to the cell-less supporting plate, the fulcral 



