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the metapterygoid (if it occurs) does not meet the hyoinandibular; 7. the lateral 

 line bones of the head are more or less reduced. In the future communications I 

 shall discuss more closely these separate features in each of the genera of the 

 group, but I may add here some brief notes regarding points 3 — 7. 



Point 3. Of the two main constituents of the cranial "beak", the vomer 

 and ethmoid, the vomer is always the longer part, reaching in general from the 

 region under the orbit to the tip of the snout, while the ethmoid only begins in 

 front of the orbit and ends at a longer or shorter distance from the tip of the 

 snout. Regarding the beak from above, however, the part of these two bones 

 which is observable on the cranial surface varies considerably; in Amphisile and 

 Centrisciis quite a small part only of the mesethmoid is seen, whilst a very long 

 anterior part belongs to the vomer; in the Syngnathidæ {Nerophis) the vomer and 

 mesethmoid each constitute approximately tlie half part of the dorsum of the beak 

 in front of tlae frontals; in Solenostoninm and Fisiularia about three-fourths of this 

 belongs to the etlimoid, a fourth part to the vomer, and in Aulostomum the ethmoid 

 extends practically to the tip of the snout. 



Point 4. In Amphisile and Centriscus we find all the components of the part 

 of the mandibulary suspensorium in question which are typical of the bony fishes 

 ingeneral, namely: palatine, ecto-, ento- and metapterygoid, symplectic and quadrate; 

 the palatine, ento- and metapterygoid form the upper edge connected with the 

 cranial beak. In Aulostomum and Fisiularia the ectopterygoid is wanting and the 

 palatine, entopterygoid and metapterygoid form the connection with the cranial 

 beak, also the symplectic in Fisiularia. In Solenostomum and the Syngnathidæ the 

 metapterygoid is wanting; in the former the palatine, entopterygoid and symplectic 

 form the connection with the cranium, just as in Hippocampus, while in Siphono- 

 sloma and Nerophis the ectopterygoid also reaches to the cranium. 



Point 6. The absence of the connection between the metapterygoid and 

 hyomandibular. which is present in the majority of the bony fishes, is a result of 

 the development of the snout into a tube; that not every elongation of the snout 

 necessitates the removal of the metapterygoid from the hyomandibular is seen, for 

 example, in Spinachia and Aulichthys where the usual connection is preserved. 



Point 7. All the lateral line bones of the head are lacking in Solenostomum 

 and Fisiularia. The nasals are only found in Amphisile and Centriscus; the infraor- 

 bitals are wanting in all the genera with exception of the so-called preorbital or 

 antorbital. This is much reduced in Aulostomum, fairly small in Centriscus, whilst 

 it is much developed in Amphisile and the Syngnathidæ. In Amphisile a row of 

 2-4 thin bony plates connect directly with its anterior end and may be regarded 

 as separate parts of it; undoubtedly homologous with these, we find in the Syng- 

 nathidæ, in front of and connected with the true preorbital, 1 bony plate (of con- 

 siderable size in Siphonostoma, smaller in Nerophis) or 2 (Hippocampus, Solenogna- 

 thus). In the Syngnathidæ a part of the lower edge of the preorbital is connected 

 with the preoperculum (whereas it is the infraorbital No. 3, which is lacking in 



