APPENDIX. 211 



in the other the reverse is the case. The papillae of the first kind are very 

 numerous, they form the "scales"; those of the second are less numerous 

 and smaller, they form the basal parts, that is, the peduncles of the bud-like 

 organs here described. Each bud-like organ is supplied with a nerve about 

 70 fjL thick (Fig. 3 n) which traverses the layers of the corium. These layers 

 bend outward around it and thus form a tubule. Besides the nerve also 

 the artery jDasses through this tube. Tlie terminal thickened part, the head 

 of the organ, consists principally of spindle-sliaped connective- tissue cells 

 with oval nuclei (Fig. 3 c) and blood vessels (Fig. 3 b). On entering the 

 organ the artery (Fig. 3 A) immediately divides to form a capillary network. 

 These capillaries decrease in width from the centre towards the periphery ; 

 the narrowest are 12 /x wide. The capillaries unite to form a vein (Fig. 3 

 v) which has the same width as the artery. This vein extends for a consid- 

 erable distance subcutaneously and does not pass through the tube in which 

 the nerve and the artery are contained. The branching of the nerve com- 

 mences at a higher level than the branching of the artery, above the centre 

 of the head. Its proximal parts bear no branches. Just beyond the centre 

 of the head it splits up into several bundles of primitive fibres. These 

 ramify and thus a mass of separate nerve fibres are produced, interlacing with 

 the capillary blood vessel net which is densest at the apex of the organ. 

 The final termination of the nerves could not be made out, on account of the 

 specimen not being specially preserved for the purpose. A continuous cuti- 

 cle covers the whole organ (Fig. 3 t). 



Organs comparable to these have been described by F. Leydig (1850, 

 p. 172, 1851, pp. 235-239) as " Nervenknopfe." These differ, however, in 

 several respects from the bud-like organs of Malthopsjs examined by me. 

 The differences in shape and size would not be important ; but the cylinder 

 epithelium which forms a principal part of the "Nervenknopfe," and to which 

 the authors attach so great an importance, is missing in the buds of Malthopsis. 

 If we were to imagine the organs of Malthopsis covered by a sensitive 

 cylinder epithelium they would be " Nervenknopfe," still, however, differing 

 from those described by F. Leydig (1. c.) in some respects. Leydig found 

 the " Nervenknopfe" always in slime canals; whilst the organs of Malthopsis, 

 are free. The "free lateral organs" described by F. E. Schulze (1870, p. 71), 

 which might also be compared to the buds of Malthopsis, are superficial 

 swellings in the floor of the lateral canals. According to B. Solger (1880, 

 Plate XVI, Fig. 6) they are oval plates. Thus these organs also differ con- 

 siderably from those of Malthopsis. Neither can the " Nervenknope " of 

 Lepicloleprus coelorhjnchm (Leydig 1850, pp. 235-239) be compared with them. 

 The term " Nervenknopfe" is hardly applicable to the organs of Malthopsis 

 because their heads are not endswelliugs of nerves, but composed of con- 

 nective tissue and abundant blood vessels. In so much as they are richly 



