y 



NATURAL SCIENCES OF PHILADELPHIA. 117 



The body is elongated and covered with moderate or rather small scales. 

 The lateral line is arched only in front, and for most of its length, course 

 nearly at equal distances from the dorsal and abdominal surfaces. 



The head is cuboid, and covered with the smooth and naked skin. 



The anus is placed far forward. The anal fin commences close behind, 

 and is very long, having nearly thirty or more rays. The ventral fins are 

 jugular, and each composed of about three simply articulated and unbranched 

 rays. 



Dactyloscopus Gill. 

 Dactyloscopus Gill, Proceedings of the Academy of Natural Sciences of Phila- 

 delphia, 1859, p. 132. 



Head above longer than wide. Preoperculum unarmed. Posterior margin 

 of the operculum fringed. Operculum, suboperculum and interoperculum 

 with membranous extended borders. Lower jaw entire. No intralabial fila- 

 ment nor mental barbal. Villiform teeth only on the jaws. Dorsal fin un- 

 armed. 



It may not be deemed unnecessary to add that the family characters above 

 given apply entirely to this genus, and that the branchial apertures are 

 equally widely extended, that the branchiostegal membrane is doubled in 

 front, and that the lips are fringed as in the other members of the family. In 

 all of those characters it differs much from any of the Blennoids. 



The genus Dactyloscopus was originally established on a species found at 

 Barbados. Mr. Poey, the learned Professor in the University at Havana, has, 

 in his correspondence, informed me that he has obtained two species in Cuba. 

 at least one of which appears to be new. Another species has been discovered 

 by Mr. Xantus, at Cape St. Lucas, and the specimens are preserved in the 

 Museum of the Smithsonian Institution. They will be described on a future 

 occasion. 



Dactyloscopus tridigitatus Gill. 



Dactyloscopus tridigitatus Gill, Proceedings of the Academy of Natural Sci- 

 ences of Philadelphia, 1859, p. 132. 

 Habitat. Caribbean Sea. 



Descriptions of forty-nine New Species of the Genus MELANIA, 



BY ISAAC LEA. 



During the past and present years, I have read several papers describing 

 new species of Unionido?- and Melanidce, kindly sent to me by E. R. Showalter. 

 M. D., of Uniontown, Alabama, a Correspondent of our Academy, who has 

 been unremitting in his exertions to make known the natural history of that 

 part of the State. In these papers there were few species of the genus Melania. 

 They were purposely delayed with a view to bring them as much together as 

 possible ; and the present paper will exhibit the vast expansion there of Zoolo- 

 gical life in this single genus, the Coosa River really appearing to be the 

 Zoological centre of this particular group. 



The great variety of form, color and size will at once strike the Naturalist, 

 and he will be surprised in the examination of these forms to observe how few 

 there are of tuberculate or plicate species, which so well characterise the 

 members of the same family, in the streams which form the Tennessee and 

 Cumberland rivers at no great distance. 



Melania Hartmaniana. Testa, lasvi, conica, magna, vel tenebroso-cornea vei 

 tenebroso-oliva, valde vittata, imperforate ; spira. obtuse conica ; suturis valde 

 impressis ; anfractibus subplanulatis, instar septenis, ultimo grandi ; aperturii 

 grandi, ovato-rhomboidea, intus brunneo-vittata, ad basim obtuse angulat:! : 

 iabro acuto ; columella incurvata. 



Hab. Coosa and Cahawba Rivers, Alabama. E. R. Showalter, M. D. 



1861.] 



