174 THE RADIATING ORGANS OF THE DEEP SEA FISHES. 



layer of tlie 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. 



Ilandrick ('01) has published a detailed account of the nervous system 

 and the radiating oi'gans of the same species. He appears to have been 

 unacquainted with Chiarini's paper cited above. Handrick ('01. p 58, 59) 

 carefully worked out the innervation for most of the radiating organs ('01, 

 pp. 58, 59). Tlie anteorbital is — as Leydig had previously stated (see p. 173) 

 — innervated by the trigemius, the postorbital, opercular, and l)ranchio- 

 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 " Leuchtkorper," is very 

 minutely described ('01, p. 55). It is not in direct contact with the fibre 

 sheath (as stated l)y Cliiariui), l)ut separated from it by a special membra- 

 nous layer of coimective tissue. From this, strands of connective tissue 

 extend inward. These are much branched and anastomizina; form a net- 

 work along which nerves and blood vessels extend, and in the meshes of 

 which large round or polyedric cells lie. The columnai- 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 lliem. According to him they al- 

 ways have only one nucleus, not sometimes two as stated by Cliiariui (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- 



