176 THE RADIATING OKGANS OF THE DEEP SEA FISHES. 



I have described ('87, p. 303, Plate 70, Figs. 15-24) the radiating organs 

 of Slernopii/x diaphaim. In that species extensive radiating organs are met 

 with on the lips, and I think that such may also be present in S. obsctira ; 

 but as that portion of the specimen at my disposal is somewhat injured 

 I cannot express myself with certainty on this point. The glandular tubes 

 as figured ('87, Plate 70, Fig. 20) in the iimer coalesced regions of the 

 ventrothoracic organs cannot be made out in S. obscura ; in this fisli they 

 appear to consist, as in Argyropelecus, of an alveolar network containing 

 large, roundish cells. 



Lychnopoles argenteolus Garman. 



Plate 7, Figs. 31-37. 



This species has been described by Garman ('99, p. 244, Plate 53, Figs. 4, 

 4a). The radiating organs appear as spots, 700 /x in diameter, with a 

 silvery lustre, and are pretty conspicuous. There are on each side 1 ante- 

 orbital (Plate 7, Figs. 31, 32 ao), 1 mandibular (Figs. 32, 33 ma), 11 bran- 

 chiostegal (Fig. 33 br) 9 guttural (Figs. 33 g), 2 opercular (Figs. 31, 32 op), 

 14 ventrothoracic (Figs. 31, 32 vt) — Garman ('99, p. 245) counts 15 of 

 these — 19 ventromedial (Figs. 31, 32 ve), 22 anal (Figs. 31, 32 a), 11 anterior 

 lateral (Figs. 31, 32 al), 10 mediolateral (Figs. 31, 32 ml), and 22 posterior 

 lateral (Figs. 31, 32 pi) radiating organs. Garman ('99, p. 245) states that 

 there are besides these two parallel rows of radiating organs on the sides 

 of the body. In the partly injured specimen at my disposal these could 

 not be made out. 



With the exception of the anteorbital organ which is somewhat peculiar 

 and which will be described below, all the radiating organs mentioned have 

 the same external and internal structure. They consist, as in Argyro- 

 pelecus and Sternoptyx, of two parts, a proximal and a distal. The proxi- 

 mal part (Plate 7, Fig. 37 A) is approximately spherical and forms about 

 three quarters of a sphere. The constriction (C) between the proximal and 

 distal part is well defined but shallow, so that the "neck " of the organ has 

 a considerable breadth. The distal part (D) appears as a broad and some- 

 what short rotation paraboloid, obliquely cut off where it abuts on the 

 surface of the body. The blood vessels in the subcutaneous connective 

 tissue surrounding the organ (b) are more numerous close to the pigment 

 sheath than elsewhere. The pigment sheath (Plate 7, Figs. 35, 37 p.) is stout. 



