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Show 900 MR. J. Y. JOHNSON ON NEW CRUSTACEANS. [Nov. 28, The species is dedicated to Dr. Alphonse Milne-Edwards, of the Jardin des Plantes, Paris, the son of the celebrated author of the • Histoire Naturelle des Crustacees,' and himself the author of several valuable contributions to carcinological science. The following dimensions were afforded by the Madeiran specimen, which has been added to the collection of the British Museum :- inches. Length from tip of rostrum to end of caudal plates . 131 of rostrum 2g Carapace, length from base of rostrum to middle of posterior margin 3^- , width near the middle 11 , height If Eyes with their stalks, length f- Superior antennae, length of peduncle l| Inferior antennae, length of lamellar palp If , width f Jaw-feet, length of external pair 4 , length of next pair 2\ Legs, length of first pair 2f , length of third pair 5\ , length of hand and fingers of third pair 1 \ Abdomen, length to end of caudal segment 6| False legs, length of first pair 4\ , length of last pair 2| Middle caudal segment, length 11 PENEEUS BOCAGEI, mihi, P. Z. S. 1863, p. 255. I will take this opportunity of stating that the Peneeus of the Tagus, described by m e under the name of P. bocagei, is identical with the P. longirostris of M . Lucas (Exploration Scientifique de 1'Algerie: Crustacees, p. 46, Atlas, pl. 4. f. 5), as I have ascertained by an examination of specimens obtained at Algiers, and by a study of M . Lucas's description. Dr. Camil Heller (Die Crus-taceen der siidlichen Europa) is of opinion that P. longirostris is itself identical with P. membranaceus, Risso, and thinks that Dr. Milne-Edwards, in his ' Histoire Naturelle des Crustacees,' vol. ii. p. 417, has inadvertently attributed to the P. membranaceus of Risso some of the characters of P. siphonocerus, Philippi (Archiv der Naturgeschichte, 1840, p. 19, t. 14. f. 3), which has a very short rostrum, whilst the true P. membranaceus has a long one. If Dr. Heller's views are correct (and I have no reason to suppose that they are not), it will be seen that the range of P. membranaceus, Risso (not Milne-Edwards), is not, as has been hitherto believed, limited to the Mediterranean. It may be useful to point out how the five known species of M e diterranean Peneei may be distinguished from one another by means of their rostra. |