. Bulletin of the British Museum (Natural History). THE "ROSAURA" EXPEDITION 147 There is a strongly curved furrow spine, about 3 mm. long; it is compressed to a blade-like form and its end is blunt. It is followed by another blunt compressed spine which is broader and may be longer, up to 4-5 mm. long ; it may be bent at its base but is thereafter straight. There is a third spine which is nearly as long but much narrower, being only sUghtly compressed. A few spinelets usually arise from near the base of this spine on the adoral side. There may be a fourth and smaller spine borne on
. Bulletin of the British Museum (Natural History). THE "ROSAURA" EXPEDITION 147 There is a strongly curved furrow spine, about 3 mm. long; it is compressed to a blade-like form and its end is blunt. It is followed by another blunt compressed spine which is broader and may be longer, up to 4-5 mm. long ; it may be bent at its base but is thereafter straight. There is a third spine which is nearly as long but much narrower, being only sUghtly compressed. A few spinelets usually arise from near the base of this spine on the adoral side. There may be a fourth and smaller spine borne on the inner end of the ventro-lateral plate, but it is usual for these plates to carry two or three large bi-valved pedicellariae, of which the outermost, about I mm. long, is larger than the inner ones. Small spinules may arise around the base of the pedicellariae, especially, in the proximal part of the arm, where there may even be four rather than three pedicellariae on each plate ; in the distal part. Fig. 4. Dorso-Iateral view of three infero-marginal plates and the adjacent paxiUae. of the arm there is only one. There are no pedicellariae in the furrow as are found in L. avicularia and L. Integra. The infero-marginal plates encroach strongly on the abactinal surfaces of the arms. They are raised into strong ridges. In the proximal part of the arm there are four large spines on each plate. Three are on the lateral edge, one above the other, the lowermost shorter than the second and third which may be 6 mm. long. The fourth and longest spine, up to 8 mm. long, arises from or near the inner edge of the plate on the abactinal surface. The spines of adjacent plates arise at different levels as a rule, so that the uppermost spine of one plate is based on the extreme adradial edge, while that of the next plate is somewhat inset, the lower spines being correspondingly displaced on every second plate. On each row of infero-marginal plates there are thus eight series of spines, those
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