320 



54 



ihidœ; Ihe leniaiiiing lliree (or Iwo) paris l)eing the ccralobranchial, a rudimentary 

 epibranchial (the latter sometimes absent) with two teeth, and, widely separated 

 I'rom the rest, the pharyngobranchial. The lourth and fifth arches only consist of 

 the ceratobranchial, that of the tilth — the "lower pharyngeal" — expands into a 

 narrow plate carrying a number of pointed teeth. 



The two „upper pharyngeals'- (PI. VI, fig. 7, 8) are joined end to end, and on 

 the ventral face each expands into a tooth-bearing lamella with its margin dorsally 

 enrolled; they are — as already stated — widely separated from the other parts 

 of the branchial skeleton, but the rows of gills are continued almost to their 

 posterior end, on the pharyngeal membrane. A comparison with the Syiujnathidœ 

 and with Fistiilaria and Aulostoma tends to show that these two pharyngobranchials 

 really belong to the second and third arches, as stated above. 



In tabular form the main features of the branchial skeleton would be: 



„.,, , Basibrancli- „ . 

 Gill-arcli jgj^ I Hypobr. 



Ceratobr. Epibr. 



Pharvngo- 

 br. 



Gill 

 rakers 



I 



II 



III 



IV 



V 



+ 



+ 



+ 



[+] 

 [+] 



+ 

 + 



Compared with the other genera, Hippocampus (PI. VI, fig. 11) would be the 

 one, which in construction of the gill-apparatus is the nearest to Solenostomtis. 



The shoulder-girdle (PI. VII, figs. ;5, 4, 5), The clavicular arch is composed 

 of 3 parts: the posttemporal (pt; supraclavicular I), the supraclavicular (II) (scl) 

 and the clavicular (cl); as in Syngnathids the postclavicular is wanting. The post- 

 temporal does not form part of the skull, as is the case in Syngnathids; seen from 

 the outer side (PI. VII, figs. 3, 5) it appears bifurcated, the upper branch suturally 

 united to the epiotic (ep), the lower one to the pterotic (sq) ; from the inner face 

 a process combines with the exoccipital. With its hind end articulates the upper 

 end of the slender and fairly long supraclavicle (scl), which in turn is articulated 

 on the outer face of the upper end of the clavicle. The clavicle (cl) resembles to 

 a certain degree that of the Syngnathids; the two processes p and p' combining 

 with the dermal plates, the first behind, the latter in front of the pectoral fin, are 

 easily recognisable as homologous to the parts in Siphonostoma or Hippocampus 

 lettered in the same way in figs. 2, 3 and 7, PI. Ill; but a great difl'erence is apparent 

 in the fact, that in Solenostomiis no connection between the clavicle and the 

 anterior vertebrae has been established; the great anterior expansion of the clavi- 

 cula used for this connection in Syngnathids is therefore absent here, the corres- 

 ponding part only being used for connection with the supraclavicle. In this point 

 some resemblance to Fistalaria is apparent; and the lower part of the clavicle 



