Mr. P. H. Gosse on a new Species of Crustacea. 313 well, and perhaps even better, developed in /. sinuosa; moreover the dentation of the septa in the original S. guadid2?ensis seems to be diiFerent. 7. Astrcea rigida^ Dana ; Prionastrcea rigidaj M.-Edw. & H.; Isojihyllia rigida^ Verrill, 1872. 8. Mussa dipsacea^ Dana ; SyvijyhylUa dipsacea, M.-Edw. & H. ; Isophyllia dipsacea, Verrill. 9. Madrepora siniiosa, Ell. & Sol. ; Isophyllia sinuosa, Ver-rill. The original diagnosis given by Ellis and Solander is rather meagre ; but as the name has got a precise meaning now hy Verrill's good description, it must be accepted for this well-marked species. 10-20. SympJiyllia sfn'gosa, S. anemone^ S. conferta, S. Aglae, S. heliantlius J S. Thomasiana, S. aspera, S. cylindrica, S. Knoxi, S. marginaiaj S. verrucosa, Duchassaing & Michelotti, 1860. ' 21. Lithopihyllia midtilamella, Duch. & Mich. 1864. 22. Isophyllia " multilamellar^'' Pourtales*. For want of sufficient material, I must leave the discrimi-nation of the actual species to future researches. It is more than probable that at least half the number of the above names will prove to be merely synonyms. XXXVIII. — On Bellidia Huntii, a Genus and Species of Crus-tacea supposed to be neic. By Philip Henry Gosse, F.R.S. [Plate X.] Family Alpheadae. Bellidia fgen. nov.), Gosse. Internal antennee very little above the external : composed of two filaments forming a right angle. P^xternal antennte with the basal plates very large. Feet : first pair small, didactyle, consimilar. Second pair long, very slender, didactyle; both, arm and wrist many-jointed. Eyes not covered by the carapace. Abdomen bent abru])tly. Tail-plates large, all undivided. * Mitasa frcKjilis, Dana, referred to Isophyllia by Verrill, is, according U) the description, n C'olpophyUia.