REPORT OF THE SECRETARY. 27 



attached to the specimens or receptacles containing them, and thus the 

 agency of an ordinary hiborer, or one unconversant with the animals, 

 can be utilized in sending- for specimens, replacing them, and revising 

 the collections. 



In accordance with the requests made, Professor Gill has prepared three 

 catalogues, one ou the arrangement of the families of mollusks, referred 

 to in previous reports; another on the arrangement of the families of 

 mammals; and a third on the arrangement of the families of fishes. The 

 last two were published in November, 1872. 



The "arrangement of the fiimilies of mammals" embraces a list of the 

 recent as well as extinct families and subfamilies of the class. Of 

 these, 136 are recognized. These are combined under fourteen orders 

 and three subclasses, the subclasses being those almost universally recog- 

 nized at the present time — mouodelphia, didelphia, and ornithodelphia. 

 TLe orders of mouodelphia have been segregated into two higher divi- 

 sions, or "super-orders," equivalent to the educabilia and ineducabilia 

 of Prince Bonaparte, but with other characters derived from the interior 

 structure of the brain; the educabilia correspond with the archencephala 

 and gyrencepliala of Owen combined, and the ineducabilia to the lissen- 

 cephala. 



"Synoptical tables of characters of the subdivisions of mammals, 

 with a catalogue of the genera," have been in part published in connec- 

 tion with and under cover of the arrangement of the families of mam- 

 mals, embracing pages 43 to 98 of that work ; only that portion em- 

 bracing the orders of educabilia has been completed, the remaining 

 portion having been necessarily deferred. In contrasted dichotomous 

 tables are given characters successively of the (1) subclasses, (2) the or- 

 ders of mouodelphia, and (3) the suborders, (4) families, and (5) sub- 

 families of each group of the educabilian mouodelphia. The " arrange- 

 ment of the families of fishes " is limited to an enumeration of the sur- 

 viving families of the class, and was especially prepared for imme- 

 diate use. The group of "fishes" is considered as an artificial combi- 

 nation, and is divided into three classes — fishes j)roper, marsipobrauchi- 

 ates, and leptocardians. The three classes contain 244 families, of 

 which the true fishes embrace 240 ; the marsipobranchiates, 3 ; and the 

 leptocardians, only 1. The families of the fishes proper are combined 

 under eighteen orders and three subclasses ; the teleostein ganoidei and 

 elasmobranchii differing inthis last respect from Miiller's — the most gener- 

 ally accepted — classification simply in the union of the ganoids and dip- 

 noans. The greatest deviation from the current classifications is the 

 constitution of the order teleocephali. In an extended introduction the 

 reasons are given for the modifications suggested. 



A large demand has been made for these catalogues for the arrange- 

 ment of other museums and collections. 



It wa3 meiitioued in the last report that a new edition of the List of 



