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DISCOVERY REPORTS 



they agree completely with A. aciitus, and as I find specimens of 3 mm. diameter of disk 

 with the mouth papillae typically developed as in the aduhs, but still with only three 

 arm spines, I cannot have any doubt but that these young specimens are actually the 

 young Amp/iioplus acutiis ; the spiniform outer mouth papilla is thus the first to develop, 

 and the species is passing through an Amphiiira stage. It may be added that I have 

 ascertained that gonads have not yet appeared in these young specimens. 



Amphioplus aciculatus, n.sp. 



St. 279. 10. viii. 27. Off Cape Lopez, French Congo, 58-67 m. 2 specimens. 



Diameter of disk 2 mm. ; arms apparently about four to five times the diameter of 

 disk. 



Scales of the dorsal side of disk coarse, with their free edge slightly raised. There is a 

 very conspicuous but somewhat irregular rosette of primary plates. The radial shields 



Fig. 27. Amphioplus aciculatus, n.sp. Part of oral side {a) and dorsal side {h). > 25. 



are rather broad, about half the length of the disk radius, and contiguous in their distal 

 half. 



Outside the radial shields there is a rounded, knob-shaped plate which carries one to 

 three small hyaline thorns. The ventral interradii are in one specimen somewhat 

 sparsely covered with rounded scales, in the other almost naked. The buccal shields are 

 rounded triangular, though with a small rounded outer lobe. The adoral plates are of 

 rather unusual shape, with a straight inner side and a very broad outer lobe, widely 

 separating the first lateral plate from the buccal shield. The outermost mouth papilla 

 is small, scale-like, the second long, pointed, spine-like; the third is short, slightly 

 pointed. The infradental papillae of moderate size, a little pointed. First ventral plate 

 rather large, with convex distal edge. The following ventral plates distinctly longer than 

 broad, contiguous, with sides and outer edge forming a slight re-entrant curve. Dorsal 

 arm plates almost circular, not contiguous. Arm spines four, on the pro.ximal joints, 

 very slender and pointed. One small tentacle scale. No indication of particular colour. 



