122 PROCEEDINGS OP THE ACADEMY OF 



been now placed in a separate one, for which, the name of Bostrichthys is 

 retained. The two genera, Philypnus and Bostrichthys, form a distinct group, 

 characterized chiefly by the presence of vomerine teeth. To this group, the 

 name of Philypni may be given : ultimately it may be found to be a separate 

 sub-family. 



Philypni Gill. 



The form of the body is similar to that of the typical Eleotroids, anteriorly 

 subcylindrical, becoming compressed, and slightly decreasing in height towards 

 the caudal fin. 



The head is elongated and depressed above, the mouth ample, the teeth 

 villiform on both the jaws and the front of the vomer. 



The branchial apertures are more or less extended forwards, but separated 

 from each other by an isthmus. 



There are sis branchiostegal rays, the four exterior of which are well devel- 

 oped, curved and compressed, the two internal are small and slender. 



The dorsal fins are separated by a considerable interval ; the ventrals ap- 

 proximated, but entirely disconnected. 



The above characters apply to the only two known genera. Subsequent 

 discoveries may necessitate their revision. The group as thus constituted, 

 differs from the Eleotroids by the presence of vomerine teeth, and the distance 

 of the dorsal fins from each other. If these characters are persistent, it would 

 seem proper to retain the group as a distinct sub-family. 



The only known genera are Philypnus Val., and Bostrichthys. Philypnus is 

 an American form, and Bostrichthys an Asiatic form. The characters of these 

 will be now given : 



Philypnus Val. 

 Synonymy, 



Philypnus Val., Hist. Nat. des Poissons, vol. xii. p. 255, 1837. 

 Platycephalus sp. Bl. Schneid., Systema Icthyologise, 1801. 

 Gobiomorus sp. Lac, Hist. Nat. des Poissons. 

 Eleotris sp. Cuv., Regne Animal, ed. ii. 



Head elongated, subconical in profile, depressed above ; mouth large, lower 

 jaw projecting beyond the upper; nostrils with raised margins, between the 

 eyes and upper jaw ; the distance between each nearly equal to that of the 

 anterior nostrils from the upper jaw, and of the posterior from the eyes. 

 Branchial apertures extending anteriorly nearly to the angles of the mouth 

 and separated from each other by a very narrow isthmus. Scales ctenoid, 

 moderate, extending on the forehead, opercula and cheeks ; pectinations of 

 those on the forehead and cheeks frequently obsolete. 



All of the scales on the body of the species of Philypnus are more or less 

 angulated posteriorly, and have the nucleus near the angle ; from this angle 

 radiating grooves and ridges diverge towards the anterior margin of the scales, 

 and are crossed by concentric strise, which terminate at the posterior borders in 

 pectinations that are often obsolete ; in other scales, especially on the fore- 

 head, the concentric striae surround a subcentral nucleus, and give to the 

 scales a pseudocycloid appearance. In young individuals the scales are much 

 more distinctly pectinated than in the adnlt. 



Philypnus dormitator Val. 

 Synonymy. 

 Cephalus seu asellus palustris, vulgo le dormeur, Plummer, MSS. fide Val. 

 Platycephalus dormitator Sloch, Systema? Ichthyologise, ed. Schneid. 

 Gobiomore dormeur Lacepede, Hist. Nat. des Poissons, vol. ii. p. 599. 

 Gobiomore dormeur Descourtilz, Voyages d'un Naturaliste. 



[April, 



