70 GUIDE TO THE AUSTRALIAN MUSEUM. 



age in point of time, this being the only surviving genus out of 

 the twenty-tive which have been described from remote eras of the 

 earth's history; (4) the Spinacidce of which two very curious forms 

 Centn'na salviani and £chh)orhi7ms spinosiis are exhibited in Case 

 1Gb; (5) the PristiophorichE and (6) the Pristidce bear a strong 

 outward resemblance to one another, but the former are true 

 Sharks, the latter true Rays ; (7) the Torpedinidoe, or " Electric 

 Rays," of which our common " Numb-fish " {Hypnos mhnigrum) 

 is a good example, and whose battery is sufficiently powerful to 

 give a most unpleasant shock ; (8) the Trygonidcs or " Sting- 

 Rays " armed with a strong serrated spine on the tail, with which 

 they can inflict a severe, and in some cases, dangerous wound. 

 Numerous species are found on our coast, the "Black Sting- 

 Ray " {Tryrjon pastinaca) being the largest, (9) the AlyliohatidcB 

 or " Eagle Rays, " some genera of which grow to an enormous 

 size, even as much as fifteen feet in breath, and attain to a weight 

 of 1,500 pounds ; Ceratoptera alfredi in the Central Hall, Upper 

 Floor, will give a good idea of this family; (10) the Chiniceridce, a 

 small but interesting family representing the suh-order Hoi ocejjhala 

 and forming a connecting link between the Chondropterygii and 

 Ganoidei ; CaUorhynchus antarcticus, the *' Elephant-fish," of 

 Bass' Straits, is the only Australian representative ; the exhibits 

 belonging to this order are placed in Cases 13a, 13b (mounted 

 and in spirits), while Case 12 in the Osteological Hall contains 

 skeletons ; the large mounted species are hung round the Central 

 Hall, Upper floor. Other families represented in the Museum 

 are (11) Notidanidce, Seven-gilled shark; (12) Scylliidce, Dog- 

 fishes; (13) RhinidcE, Monk or Angel fish; (14) Rhinohatidce, 

 Shovel-nosed, and Fiddler Rays, and (15) Raiidce, true Rays or 

 Skates. 



Order GANOIDEI— Of this order, a fairly representative 

 series is on exhibit, six of the eleven living genera being on view 

 in Case 13a. These are as follows: Families (1) Sirenidce, re- 

 presented by Protopterus annectens from Tropical Africa, and 

 Ceratodus forsteri, the only Australian representative of this almost 

 extinct order ; (2) Acipenseridce, by the Sturgeons, natives of the 

 northern heniisphere, and valuable commercially as affording the 

 best quality of isinglass and caviare ; (3) Poly odontidm, by Polyodon 



