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Show 1879.] MR. F. J. BELL ON THE ECHINOIDEA. 661 bifurcate, so that the two processes thereby formed are longer than in T. angulosus. The species of the genus m ay now be briefly defined :- T. angulosus.-Test varying greatly in form and colour, the spines short and generally white; in the majority of specimens there are well-marked bare spaces in both ambulacral and interambulacral areas; there are distinct though delicate and short ascending and descending processes connecting each tooth with its alveolus ; and the radii terminate in two shorter processes. The poriferous zones are wider, the actinal system larger, and the anal and abactinal systems more extensive than in T. esculentus. The species has been found in the Red Sea, Mauritius, the Cape of Good Hope, Rodriguez, the Philippines, and at Cayenne. T. esculentus.-The test is generally rounded and more constantly white or pinkish in colour; the spines, which are white, are longer than in T. angulosus; and the median spaces in the ambulacral and interambulacral areas are ordinarily occupied by tubercles of some size ; the pieces connecting each tooth with the alveolus are shorter and more horizontal in direction; and the two processes of the radii are longer than in T. angulosus, while the poriferous zones are narrower, the actinal system smaller, and the anal and abactinal systems less extensive than in T. angulosus. As I have only seen one specimen of T. depressus, it will perhaps be best to leave the statements which I made regarding it as they stand in the body of the paper. I append a list of the localities from which the Trustees of the British Museum have received specimens. TRIPNEUSTES ANGULOSUS, Leske. a. Gulf of Suez; with some spines; pentagonal in shape. 6. Red Sea. c. "Mauritius." d. " Isle of France ;" with spines. e. Cape of Good Hope ; with spines. /. Isle of Masbate. g. Philippines. h. Reef of Oomaga ; with spines. i. Rodriguez ; with spines. j. Cayenne1. TRIPNEUSTES ESCULENTUS. a. Nassau, New Providence, W. I. b. West Indies ; with spines. TRIPNEUSTES DEPRESSUS. a. Gulf of California; with spines. 1 This is a most remarkable locality, and I suspect very strongly that it is a slip for Cayor ; but even in that case the locality is one from which the species has not yet been recorded. |