NATURAL SCIENCES OP PHILADELPHIA. 187 



heavy, and are very pilose. The eyes are large and very prominent. The 

 dorsum is slightly convex, and is ornamented on each side by a broad fuscous 

 stripe, which is intersected by numerous, indistinct, dark lines. 



The scuta are very smooth, and have no distinct lateral plates, but their 

 edges are rather thin and strongly elevated. The penultimate scutum is much 

 broader than its neighbors. The last scutum is very small. The feet are dark 

 colored. There are two or three specimens in the possession of the Academy, 

 which, I believe, were collected by Dr. John L. Le Conte, U. S. A., in the moun- 

 tains of Georgia. 



Family BIPUONOPHORIDJE. 



Genus BRACHYCYBE. 



Rostrum acutum, brevissimum, antennis multo breviore. 



I have never studied the allied genus Siphonophora of Brandt, but, if the 

 characters relied on by that author are at all generic, there can be no doubt 

 that the American species belongs to a distinct genus. In the Siphonophora 

 the rostrum or mouth is very much elongated, and approaches the antennae in 

 length. In Brachycybe the latter are several times the longer. 



B. leconth, Wood. 



Fulvo-brunneus? dorsomodice convexo, medio leviter canaliculato; antennis 

 parvis, filiformibus, pilosis ; scutorum superficie asperata, obscure transverse 

 canaliculata ; scuto postremo postice spina? obtusse serie instructo ; laminis 

 lateralibus longis, angustis, vix sejunctis ; segmentis 47 ; pedibus breve pilosis. 



In our specimens, which have been preserved for a long time in alcohol, the 

 color is a light yellowish-brown. The anterior scuta are tuberculate, the pos- 

 terior merely roughened. Each has a more or less obsolete transverse groove 

 extending along the lateral lamina. The latter are very long and narrow ; they 

 are placed very close together, and are often bent slightly backwards. Their 

 external margin is somewhat oblique, and is furnished in all except, perhaps, 

 the most anterior, with a pore. The small feet are entirely concealed beneath 

 the broad body. The male genital appendages consist of two pairs of acute 

 feet-like processes. It affords me much pleasure to dedicate this species to 

 Surgeon John L. Le Conte, U. S. A., as an acknowledgement of the many as- 

 sistances which he has afforded me in the prosecution of my studies. 



Ilab. Georgia. Coll. of the Acad. Alus. Comp. Zoology. Dr. John L. 

 Le Conte, U. S. A. 



Note on the PARALEPIDOIDS and MICROSTOMATOIDS, and on some Pecu- 

 liarities of Arctic Ichthyology. 



BY THEODORE GILL. 



My attention having been attracted to the resemblance between the Alepido- 

 sauroids and Paralepidoids, shortly after my article on new species of the 

 former family, I embraced the oppjrtunity, when in Philadelphia, to examine 

 the specimens of the two genera, 1'aralepis and Sudis, in the Bonaparte col- 

 lection, secured by the liberality of Dr. Wilson. The suspicions of the close 

 affinity of the two families were fully confirmed, and the same logic that would 

 prove the Alepidosauroids to be Siluroids, would cover the Paralepidoids. 

 Nearly equally erroneous would be the reference of those families to the Scom- 

 broid group, near which I formerly retained it with Lowe. The Paralepidoids 

 are, indeed, chiefly distinguished from the Alepidosauroids by the small dorsal 

 fin, and the more posterior ventrals, and wherever one is placed, the other 

 must be approximated next to it. 



The species of this family of Paralepidoids are divisible among three groups, 



1864.] 



