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- 



