NATURAL SCIENCES OF PHILADELPHIA. 77 



small medial interoccipital. Eye small, resting on the labials, which are not 

 pitted ; pre- and postoculars present ; pupil elliptic, erect. Teeth slightly 

 longer on the anterior parts of the dentigerous bones than on the posterior. 

 Intermaxillary bone toothless ; supraorbital bone none. 



L. bicolor possesses three postocular plates ; one large preocular is ex- 

 tensively in contact with the vertical ; the latter plate presents an obtuse 

 angle anteriorly, and is nine-sided. Superior labials ten, fourth and fifth en- 

 tering the orbit. Twelve inferior labials. One pair of very narrow geneials, 

 with a sulcus between them, and separated from the labials laterally by a single 

 narrow plate on each side. Scales in thirty-four longitudinal rows ; those of 

 the inferior, half as wide as the gastrosteges. The tail and upper surface of 

 the body, between the fourth rows of scales on each side, are of a rich purplish 

 brown. Belly, chin, and upper labials yellow. One specimen brought by 

 Capt. J. M. Dow, from La Union, San Salvador, and presented to the Smith- 

 sonian Institution. No. 4948. 



April \th. 

 Mr. Lea, President, in the Chair. 



Thirty-nine members present. 



A paper was presented for publication, entitled 



" Description of a new genus (Strephobasis) of the family Melaniadas, 

 and three new species, by Isaac Lea," and was referred to a Committee. 



Dr. Leidy mentioned that lignite had been discovered at the border 

 of the new red sandstone on Plymouth Creek, near Norristown, Pa. 



The death of Dr. John E. Evans, a correspondent of the Academy, 

 was announced; he died at Washington, D. C, on the 13th inst. 



A communication was made by Mr. Theo. Gill on several new generic types 

 of fishes contained in the museum of the Smithsonian Institution. 



The first was referred provisionally to the Agonoids, as an Agonoid under the 

 guise of a Peristedion. It presented a very strong resemblance to the represen- 

 tatives of tbe latter genus, and would doubtless, at the first glance, be con- 

 ceived to be very nearly allied to them. But with the same form as Peristedion, 

 it has the head constructed on essentially the same plan as that of a true Ago- 

 nus. The first suborbital bone expands inferiorly ; the second covers the cheek, 

 and both are armed with an inferior submarginal crest: the crest of the second 

 has a median curved spine, from which radiating grooves and ridges ad- 

 vance on the surface. Tbe snout, like that of Agonus, has on each side two 

 spines, one horizontal and the other curved backwards. The dorsal fin is 

 separated by several plates from the head. The thoracic region is covered with 

 about three rows of more or less hexagonal plates, except in front, where there 

 are only two plates. The ventral fins are approximated, and received in an 

 elongated triangular groove or furrow. In allusion to the last named peculiar- 

 ity, the genus was named Podothecus. 



The family of Agonoids is now increased by this addition so as to include at 

 least five described genera; they are the following: 



Podothecus Gill. 



Agonus Block = Aspidophorus Swainson, 



Brachyopsis Gill = Agonus Swainson. 



Hippocephalus Swainson. 



Aspidophoroides Lac. = Canthirhynchus Swainson. 



The new Agonoid was obtained by Dr. Kennedy, the zoologist of the North- 



1861.] 



