198 Mr. F. P. Pascoe's Catalogue o/Zygopinae 



dred of them miglit therefore have been expected to occur ; 

 not one has been found. 



This peculiar character alone would seem sufficient to sepa- 

 rate generically the so-called Ceratodus Forsteri from Dipterus 

 and CtenoduSj and shows very clearly the relationship of the 

 former to Lejndosiren, which is provided with two small 

 pointed teeth in front of the upper dental plates*, which latter 

 do not differ much from those of this interesting Australian fish. 



EXPLANATION OF THE PLATES. 

 Plate XIII. 



Fig. 1. Mandible, natural size, with the dental plate attached, of Ctenodus 

 imbricatus : a, dental plate ; b, f?lenoid notch. 



JFiff. 2, Outside view, natural size, of the right ramus, with the dental 

 plate attached, of Ctenodus obliqmis: a, dental plate ; 5, sym- 

 physial margin ; c, glenoid notch ; d, channel or cavity over- 

 hung by the dental plate. 



Fig. 3. Scale, much enlarged, of Ctenodus ehgans : a, posterior or imbri- 

 cated extremitj'. 



Plate XIV. 



The palato-pterygoid bones, natural size, with dental plate attached, of 

 Ctenodus ti(bercidatus : a, anterior extremity of the bone ; 

 b, dental plate ; e, palatal side of the bone ; d, pterygoid side 

 of ditto. 



XXIV. — Catalogue o/Zygopinse, a Suhfamily q/'Curculionidfe, 

 found hy Mr. Wallace in the Eastern ArcMjyelago. By 

 Feancis p. Pascoe, F.L.S. &c., late Pres. Ent. Soc. 

 [Plates XV. & X\T:.] 



For the Zygopinas of America and of the Old "World Lacordaire 

 sought to establish two sections depending on the, as a rule, 

 greater breadth of the episterna of the metathorax in the 

 former, and their narrowness in the latter, or, when in the 

 latter the episterna are broad, on there being a funicle of only 

 six joints, and the pectoral canal being absent. But, even 

 with these limitations, the distinction will not now hold good, 

 as several genera have broad episterna, either with a pectoral 

 canal or with a seven-jointed funicle. 



Lacordaire, however, was acquainted with but three of these 

 Malasian genera, only one of which [Arachnopus) has narrow 

 episterna ; and this, with Sphadasmus, Sympiezopus, and their 

 allies, it seems to me, had better be excluded from the sub- 

 family. It is not at present my intention to swerve from 

 Lacordaire's arrangement ; still it may be desirable to show 

 how the New- World ZygopinjB may be differentiated from the 



* " Description of tlie Lepidosiren annectens,^^ by Richard Owen, Esq. 

 Trans. Liim, Soc. vol. xviii. p. 341, tab. 27. fig. 2. 



