174 THE RADIATING ORGANS OF THE DEEP SEA FISHES. 
layer of the organs of A. hemigymnus is not quite continuous, but inter- 
rupted by longitudinal lines free from pigment. The fibre layer is ex- 
ceedingly thick. The internal tissue has no special covering membrane 
and is in immediate contact with the fibre layer. The inner region of 
the internal tissue is composed of polygonal cells. Each contains granules 
and one or two nuclei. These cells are not regularly arranged; there 
is, however, an indication of a concentric stratification near the outer limit 
(towards the middle region). The cells of this inner region are supported 
by reticulate connective tissue. The middle region is composed of cells 
with a polygonal contour, arranged transversely. In the outer region the 
cells are arranged more or less longitudinally. Also in this middle region 
a supporting reticulation of connective tissue is met with. The distal 
portion of the cone is occupied by gelatinous tissue. 
Handrick .(’01) has published a detailed account of the nervous system 
and the radiating organs of the same species. He appears to have been 
unacquainted with Chiarini’s paper cited above. Tandrick (01, p 58, 59) 
carefully worked out the innervation for most of the radiating organs COL, 
pp. 58, 59). The anteorbital is —as Leydig had previously stated (see p. 173) 
—innervated by the trigemius, the postorbital, opercular, and branchio- 
stegal by the facialis, the others by spinal nerves. The radiating organs are 
not movable relative to the body (versus Brandes, see p. 173) but the con- 
cavity of the sheath can be changed by muscular action (01, p. 54). A few 
very elongated nuclei belonging to the fibre cells were observed in the in- 
ner sheath. The tissue of the inner region, the “ Leuchtkérper,” is very 
minutely described ('01, p. 55). It is not in direct contact with the fibre 
sheath (as stated by Chiarini), but separated from it by a special membra- 
nous layer of connective tissue. From this, strands of connective tissue 
extend inward. These are much branched and anastomizing form a net- 
work along which nerves and blood vessels extend, and in the meshes of 
which large round or polyedric cells lie. The columnar arrangement de- 
scribed by Leydig (81, p. 31, see p. 173) cannot be made out. Handrick 
(01, p. 56) gives a detailed description of the internal structure of these 
cells and distinguishes two varieties of them. According to him they al- 
ways have only one nucleus, not sometimes two as stated by Chiarini (see 
above). The tissue of the middle region is, according to Handrick (01, p. 57), 
also supported by a reticulation of connective tissue. He considers the cells 
forming its proximal portion as spindle shaped, those forming the distal por- 
