THE RADIATING ORGANS OF THE DEEP SEA FISHES. 2038 
I. murrayi, and has examined and carefully described their minute struc- 
ture. In the material of J. agassizii at my disposal these discs are not suffi- 
ciently well preserved to allow of their minute structure being studied. 
All I can say is that I have seen nothing in them that would justify one in 
supposing that they differed in any way from the organs described by 
oo 
Moseley in 7. murray’. The hexagonal cylinder cells of the dises of J. 
agassizii are about 20 pw long and 6 p thick. 
(8) THE FISHES WITH TUBULAR RADIATING ORGANS. 
Malthopsis spinulosa Garman, 
Plate 1, Figs. 1, 2, Plate 2, Figs. 6-9. 
This species has been described by Garman ('99, p. 106, Plates 21, 24). It is 
(Plate 1, Figs. 1, 2) a flat fish of horseshoe-shape with a stout conic tail. 
The organ here to be deseribed which may have a radiating function is 
a medial tentacular papilla on the forehead just above the mouth (Plate 2, 
Fig. 6 te). Garman (99, p. 106) states that this papilla is contractile and 
can be extended and retracted at the will of the fish. In the state observed 
by me it is about 6 mm. long and 1.5 mm. thick. This papilla is situated in 
a depression so that it protrudes when retracted only slightly beyond the 
general surface of the fish. The apex of the papilla is divided into three 
lobes, an upper somewhat leaf-shaped one and a pair of lower massive 
ones. 
The trilobed terminal part of the tentacular papilla of the only specimen 
of Malthopsis spinulosa at my disposal was cut into a series of transverse 
sections. These (Plate 2, Figs. 7, 9) show that its trilobed distal part is 
stout longitudinal rods of semicartilaginous tissue (Figs. 
supported by four 
upper ones joined to 
8, 9s). The two lower ones are separate, the two 
form a band-shaped structure. These rods are enclosed in sheaths of con- 
nective tissue from which septa (Figs. 7, 8, 9 ce) radiate, chiefly into the 
the interior of which is divided by them into a 
massive ventral lobes, 
Tn the middle of the ventral surface 
number of longitudinal compartments. 
connecting the two ventral lobes a conspicuous longitudinal ridge is ob- 
s occupied by a pair of longitudinal muscles, 
served, the interior of which i 
are, no doubt, the muscles which 
lying close together (Migs. 8, 9 mj. itese 
retract the tentacular papilla, while its extension is probably brought about 
