HEMIBE.VNCHII. 
369 
SjpJiyrcena sternhergensis, T. C. 'Winkler, Archiv Tereins Fr. 
Xaturg. Mecklenburg, vol. xxix. (1875), p, 123, pi. iii. 
figs. 17, 18.—Upper Oligocene ; Sternberg. [Jaw and 
. scale.] 
Sg>hyrcena luiiikleri^ E. Lawley, Xuovi Studi Pesci, etc. Colline 
Toscane (1876), p. 77.—Lower Pliocene; Orciano, Tus¬ 
cany. [Teeth.] 
The so-called Sphyrc^na amici (L. Agassiz, Poiss. Foss. vol. v. 
pt. i. 18T3—14, p. 97, pi. x. fig. 3) is founded on remains of a skull, 
not of this genus, from the Upper Cretaceous of Mount Lebanon. 
With the Percesoces are sometimes placed the Ophiocephalid.!:, 
a family of freshwater fishes common in the Indian region, rarer 
in Africa. Xo extinct representatives are definitely known, but 
the following fossils have been referred to the existing genus 
O'phioce^licilus :— 
15374-75, 16402,-a. Four fragmentary heads ; Siwalik Formation 
(Pliocene), Siwalik Hills, India. Xoticed by E. Lydekker, 
Palmont. Indica, ser. x. vol. iii. (1886), p. 246, the third 
specimen being figured, loc. cit. pi. xxxvii. fig. 2, also 
noticed by J. M‘Clelland, Calcutta Journ. Xat. Hist, 
vol. iv. (ikl), p. 83. 
Presented hy Col. Sir Proby T. Cautley^ K.C.B., 1842. 
Suborder YIII. HEMIBRANCHIL 
Yertebral centra always complete constricted cylinders, those 
immediately behind the occiput more or less modified or coalesced. 
Supraoccipital extending forwards between the reduced parietals : 
squamosal rudimentary and fused with the large pterotic ; mandible 
simple, each ramus consisting only of two elements (dentary and 
articulo-angular). Branchial arches always more or less reduced. 
Pectoral arch suspended from cranium; large infraclavicular plates 
present: pectoral fin with not more than four or five basals. 
Pelvic fins usuallv abdominal, but sometimes advanced so that their 
supports are in contact with the pectoral arch. Dorsal fin with 
or without an anterior spinous portion. In the living forms :— 
air-bladder closed, without pneumatic duct, in the adult (physo- 
clistous) ; optic nerves decussating; intestine without spiral valve. 
Following the suggestions of Kner and Steindachner ^ and Cope ^ 
^ Denksehr. k. Akad. Wiss., math.-naturw. Cl. vol. xxi. (1863), p. 28, footnote. 
^ E. D. Cope, Origin of the Fittest (1887), p. 328. 
PAET IT. 2 B 
