382 Dr. A. Giiuther'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 ^ inch ; thickness i£ inch. 



Loc. Valley of Kelat (Dr. Cook). 



Associates. — Found in the bed of diminutive Foraminifera 

 mentioned under the head of N. kelatensis. 



Obs. — The Alveolina {A. Boscii) described and illustrated by 

 Dr. Carpenter (Phil. Trans. 1854) is classed by him with Orbi- 

 tolites, or D'Orbigny'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 (el,/2), 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 affect 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 allied species, and begins to vai*y only where the 

 number of rays is very great, as in Labrus. Out of the forty genera 

 proposed, five, viz. Semicossj/phus, Pteragogus, Cirrhilabrus, Oli- 

 stherops, and Malapterus, I have not seen. The three latter, 

 however, are so well described and figured, that no doubt re- 



