308 



42 



Nerophis. 



Hippocampus. 



Pectoral skeleton. Nerophis has no pectoral fins in the adult state; only 

 the larvæ possess well-developed pectorals, but without rays. In Nerophis the 

 "pectoral ring" is composed mainly as in Siphonostoma, the only difference being 

 that the second nuchal plate is joined to the clavicle, and the "cover-plate" is ab- 

 sent. As there is no slit in the armature for the missing pectoral fin the lateral 

 plate of the following ring joins firmly on to the clavicle. 



The clavicle is of the same type as in Siphonostoma, but every trace of the 

 scapular arch has vanished together with the fin-muscles. 



In Hippocampus (and its allies) the clavicular and scapular arches and the 

 pterygials are in the main as in Siphonostoma"". The pectoral ring does not 

 materially differ from that of Siphonostoma. Comparing the figure (PI. Ill, fig. 3) 

 with the other one (fig. 2), the same constituents will easily be found. In Hippo- 

 campus there are 3 nuchal plates, the posterior is generally not to be found in the 

 Syngnathine group. The anterior fig. 3 n' is of very peculiar shape, joining the 

 skull and apparently forming the top of the bent head, often described as the 

 "corona". This part is wanting in some members of the Hippocampine group 

 (Gasterotokeus, Phyllopteryx) but present in Solenognatlius'K In Phylloptergx the 

 hindmost nuchal is provided with a long bony style, like the top of the supra- 

 occipital, and several (paired) styles from the dermal armour supporting the curious 

 dermals flaps characteristic of the genus. 



