HYALONEMA (PRIONEMA) AGUJANUM. 
251 
Hyalonema (Prionema) agujanum, sp. nov. 
tenuis, var. nov. Form A. 
Plate 72, figs. 17-21, 23-25, 27; Plate 73, figs. 1-6; Plate 74, figs. 1-5, 8; Plate 75, figs. 1-13, 15, 17, 
19-27, 29-37; Plate 76, figs. 1-7, 11, 12, 15-36. 
tenuis, var. nov. Form B. 
Plate 72, figs. 16, 22, 26; Plate 73, fig. 7; Plate 74, figs. 6, 7, 9; Plate 75, figs. 14, 16, 18, 28; Plate 76, 
figs. 8-10, 13, 14. 
lata, var. nov. 
Plate 77, figs. 1-10; Plate 78, figs. 1-15. 
I establish this species for five specimens collected off northern Peru, near 
Aguja Point, at Station 4656 on 13 November, 1904; 6° 54.6' S., 83° 34.3' W. ; 
depth 4063 m. (2222 f.); they grew on fine, green mud mixed with gray ooze; 
the bottom-temperature was 35.2°. The specific name refers to the locality. I 
distinguish two varieties in this species, one comprising four specimens, with 
narrow, one comprising one specimen with broader serrated amphidisc-anchors. 
In view of the difference in the anchor-breadth of these amphidiscs, I name the 
former tenuis, the latter lata. One of the four specimens of var. tenuis differs 
somewhat from the other three; I therefore distinguish two forms, A and B, in 
this variety. Form A comprises three specimens, form B one. 
Shape and size. All the specimens (Plate 75 , figs. 28-30; Plate 78 , fig. 4) 
are inverted, conical, and more or less flattened laterally. The better preserved 
ones have a broad and shallow depression on their upper face and a stalk which 
arises from the lower narrow end. I consider the apical depression a gastral 
cavity. In one specimen the remnant of a gastral cone is visible in its centre. 
The specimens are 19-29 mm. long, 23-30 mm. broad, and 8-16 mm. thick. 
The stalks present are broken off quite short. The longest is 24 mm. long. A 
few Palythoa polyps are attached to the proximal part of the stalk just below 
the point where it arises from the body (Plate 75 , figs. 29, 30; Plate 76 , fig. 7). 
The colour of all the specimens in spirit is brown. 
The skeleton. The dermal and gastral surfaces are entirely covered with a 
dense fur composed of the distal rays of pentactine pinules. In the spicule- 
preparations a good many diactine pinules were found. These in all probability 
occupy the margin of the apical (gastral) cavity. In the subdermal and sub- 
gastral zones radial pentactines and paratangential rhabds are met. Similar 
rhabds, hexactine megascleres, and microhexactines occupy the interior. Here 
