382 Dr. A. Giiiither's Synopsis of the Labroid Genera. each chamber extending from pole to pole, and each layer covered with a cortical tubular reticulation. Largest size. — Length |4 i'lch ; thickness -^ inch. Loc. Valley of Kelat (Dr. Cook). Associates. — Found in the bed of diminutive Foraminifera mentioned under the head of N. kelatensis. Ohs. — The Alveolina (A. Boscii) described and illustrated by Dr. Carpenter (Phil. Trans. 1854) is classed by him with Orbi-tolites, or D'Oi-bigny's " Cyclostegues.^^ That which I have described under the name of A. elliptica must be classed with Nummulites or the " Helicostegues " of D'Orbigny. It begins spirally from a central cell like Operculina, &c. {d), and as the chambers increase, so they become extended vertically on both sides, but go beyond the sigmoid form of the chambers of A. elliptica in becoming tortuous ; so that the surface of the test pre-sents the wavy appearance of the surface of Nummulites gyzehensis when the superficial incrustation is dissolved or rubbed off [a). A canal-system (el,/2, 3) can also be easily perceived at the commencement, which follows the margin or surface of the spiral lamina and the interseptal spaces respectively, assuming a reti-culated structure in the former [e\,f2), supported on a series of straight canals (/3) in the latter, which seem respectively, also, to answer to the horizontal and interseptal canals in A. elliptica, and to the marginal plexus and interseptal canals in Operculina and Nummulites. [To be continued.] XXXVIII. — A Preliminary Synopsis of the Labroid Genera. By Dr. Albert Gunther. During my examination of the Labroid fishes, I have found it necessary to propose a more natural arrangement of the genera of that family. As the alterations suggested afi'ect the greater number of the genera which had been previously established, I have considered it useful to give an abstract from the manu-script of the fourth volume of the ' Catalogue of Fishes ' before its publication, in order to assist others who may engage in similar investigations, or to receive from them better informa-tion. Too little attention has been hitherto paid to the number of the fin-rays in generic division : this character is very con-stant in the aUied species, and begins to vary only where the number of rays is very great, as in Labrus. Out of the forty genera proposed, five, viz. Semicossyphus, Pteragogus, Cirrhilabrus, Oli-stherops, and Malapterus, I have not seen. The three latter, however, are so well described and figured, that no doubt re-
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