Clas.-^ijicatioti of (he Order Microcyprini. 321 



There remain, tlien, for consideration only the Esocidse, 

 Unibiida?, and Dalliidaj, tiie Ilaplonii sensa strictu, and the 

 Cyprinodontidre and Amblyopsidse, for which 1 have proposed 

 the ordinal name ]\ricrocyprini. 



Tiiese two groups resemble each other in the absence of a 

 niesocoracoid and an orbitosphenoid, tlie separation of the 

 parietals by the supraoccipital, &c., but they differ widely in 

 other respects, and do not seem to be closely related. 



The Haplomi are physostomous, the maxillary enters the 

 gape, the niesefhmoid is represented by a pair of dermal 

 bones, and the ribs are borne on autogenous parapophyses*. 

 The Microcyprini appear to be pliysoclistic, the month is 

 bordered above by tlie praimaxillaries only, the mesethmoid 

 is unpaired, and all or most of the ribs are inserted on strong 

 transverse processes. Whereas the Haplomi show relation- 

 ship to the most generalized isospondylous fishes, the Micro- 

 cyprini bear more resemblance to the ISalraopercse and 

 yynentognatiiij especially the latter. 



Order .MICROCYPRINI. 



J^lalacopterous physoclists with abdominal pelvic fins, each 

 of 6 or fewer rays. No lateral line. Mouth terminal, 

 bordered above by the prgemaxillaries ; second, third, and 

 fourth upper phaiyngeals deiitigerous ; lower pharyngeals 

 either separate, or if united with tlie median suture persistent ; 

 branchiostegals 6 or less. Parietals separated by supra- 

 occipital ; mesethmoid unpaired ; no orbitosphenoid ; ali- 

 sphenoids well separated; basisjihenoid, when present, small, 

 free superiorly ; roof of niyodome membranous or thinly 

 ossitied ; a short occipital, but no parietal crests. Pectoral 

 arch attached to skull; })Ost-temporal foiked, or the lower 

 limb sometimes ligamentous ; supra-cleithrum small ; no 

 niesocoracoid ; radials 4, short and broad, 2 or 3 on hyper- 

 coracoid. Vertebral column of solid centra which are 

 co-ossified with the arches; all or most of the prsecaudals 

 with strong parapophyses bearing the ribs ; epipleural;-, but 

 no epineurals ; ribs commencing on second vertebra ; no 

 up urned centra at base of caudal fin; hypurals ankylosed 

 with the last centrum. 



I have examined a number of genera, and I believe that 

 all are physoclistic, but I have not undertaken the detailed 

 research necessary to establish this. Valenciennes came to 



* Cf. StarL-.s Biol. Bull. vii. 1904, p. 254, and Zuol. Jahrb. 1904, 

 p. 249. 



