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Show 144 PROF. F. J. BELL ON ECHINODERMATA [Feb. 15, PSEUDOCUCUMIS ACICULA. (Plate XVI. fig. 5.) A single specimen of this rather rare species, the spicules of which I have had figured, as their representation seems to be more satisfactory than those of Prof. Semper. MUELLERIA MILIARIS. Some of the specimens which I associate under this name differ from M. lecanora in that the region of the anus is not lighter than the rest of the dorsal surface; on the other hand, the sharp distinction between the dark brown of the bivial and the light colour of the trivial surface is an indication of affinity to M. lecanora. Considering the closeness of the resemblances and the slightness of the differences between M. miliaris and M. lecanora, I feel inclined to suggest that the species should be united. One specimen is of a uniform chocolate-brown colour. HOLOTHURIA ALBIDA. (Plate XVI. fig. 6.) Body elongated, tapering somewhat at either end ; tentacles darker (? twenty) ; suckers sparse, scattered. Body-wall thin ; oesophageal ring very feeble; Polian vesicle double; lungs poorly developed. The specimen examined had no genital tubes. The largest specimen was 180 millim. long, had a greatest width of 35 millim., and was 18 millim. wide in the region of the anus. The flat plates are very irregular in form ; the turriform bodies have a single connecting bar, and are knobbed at the narrower end, or where the bar is developed; at the wider end there are also knobs, and these are surrounded by rather coarse spines (Plate XVI. fig. 6). The position of this species in the keys of Lampert cannot as yet be exactly determined, owing to the retracted condition of the tentacles ; it clearly belongs to the group of " Aspidochirote Formen mit Stiihlchen und glatten Schnallen," and those in which the Schnallen are irregular. Like H. immobifis, it has two Polian vesicles; but it differs in colour, in the arrangement of its suckers, and the form of its spicules. Like H. pardalis, it has a number of regular plates, but it wants the characteristic marking of that species, and is of much larger size than any known examples. HOLOTHURIA CADELLI. (Plate XVI. fig. 7.) Body rounded, tapering posteriorly, dark above, lighter below ; prickly papillae, not so numerous or prominent as in H. squamifera, frequently but not always with a white circular base. Body-wall thin. Tentacles (retracted) ; oesophageal ring small and inconspicuous, the anterior region so contracted that the disposition of the Polian vesicles cannot be certainly made out. Cuvierian organs in the form of rather numerous stout caecal tubes from half to one inch in length. Lungs well developed. Genital tubes numerous and extensive. The flattened spicules are (Plate XVI. fig. 7) of the type of those found in H. albiventer, but the knobs are more numerous, and |
