20 



oil and two parts of olive oil; one part of this 

 to be added to twenty-five parts of common 

 tar. Rope prepared in this manner was sub- 

 jected to abundant tests. It was found to be 

 equally pliable in cold and warm weather : 

 a twenty-six inch cable, made for the 

 Ship of the Line Columbus, was handled as 

 readily in January as in August. The strength 

 of Russia hemp was found to be actually in- 

 creased by this mode of tarring, about five 

 per cent, whereas by the common mode it 

 was diminished about twelve per cent. — 

 "With American hemp a like increase of 

 strength was not gained. 



Mr. Swan deems that a portion of the ad- 

 vantage is derived from the lower tempera- 

 ture at which the tar can thus be applied. 



Mr. T. J. Nevins exhibited a number of 

 specimens of Ostraea and Mytilus from Con*- 

 tra Costa. 



Dr. A. Kellogg exhibited a drawing and 

 specimen of a Willow brought from the Te- 

 jon Pass by Col. Ransom, allied to S. mcana, 

 Mx. 



Dr. W. P. Gibbons exhibited a drawing of 

 a naked Mollusk from Saucelito, promising 

 a description at a future meeting. 



Dr. A. Kellogg presented the following de- 

 scription of a Fern from Shoalwater Bay. 



Polypodium jalcatum, Kellogg. — Sickle-leaf 

 Polypod or Liquorice Fern, .r/rond deeply 

 pinnatifid, segments alternate, long lance 

 ialcate, attenuate, acuminate, doubly serrate, 

 upper and lower divisions smaller by degrees. 

 terminating above in a long Blender acumin- 

 ation. Sori numerous, 20 to 24 in two rows, 

 one on each side of the mid-iib, rachis glab- 

 rous from 1 to 1 1-2 feet in height. Root 

 compressed tuberculate 1-4 to 1-8 inch broad, 

 greenish russet color, branching laterally, 

 radicles numerous, rhizoma often covered 

 with scales. Kpiyhytic on old decayed trees, 

 stump«, roots and clefts of rocks. 



This species was sent from Washington 

 Tenilory by Mr. J. G. Swan. It is highly 

 esteemed as a medicine, both among the na- 

 tives and others, thought to be antisyphilitic, 

 also used in the preparation of tobacco, impar- 

 ting to it a sweetish liquorice tlavor. — 

 The Polypody upon oak trees was famous 

 among the ancients for the cure oi lnchm- 

 ly and madness, I 



Dr. Wm. 0. Ayres presented descriptions, 

 with the specimens, of two new Cyprinoid 



fish. 



Lavinia gibliosa, Ayres — The length of the 

 specimen employed in description is eleven 

 and a half inches; the species appearing sel- 

 dom to exceed this size to any great decree. 



Form robust, the depth being contained 

 only three times in the length not including 

 the caudal fin; the depth at the caudal fin 

 equals half the greatest depth; the thickness 

 anterior to the dorsal fin is about two thirds 

 of the depth at the same point. Head rath- 

 er small, though not distinguished from the 

 body by any depression, and not at all con- 

 cave in its dorsal outline; length of the head, 

 contained live times in the total length. — 

 Eves oearly circular, with their diameter not 

 quite equalling one filth of the length of the 

 head. Mouth small, with its line of closing 

 oblique; the tip of the maxillary not reach- 

 ing to the edge of the orbit; the lower jaw 

 shorter than the upper. 



The posterior border of the opercular appa- 

 ratus forms a regular curve. 



Anterior aperture of the nostrils smaller 

 than the posterior. 



The lull ml line curves gently downward, 

 nearly as far as the insertion of the ventral 

 fins, and thence runs straight to the caudal 

 fin. 



The origin" of the dorsal fin is nearer to the 

 caudal rays than to the tip of the snout. The 

 lirst three rays are merely rudimentary; the 

 fifth is the highest, equalling one sixth of the 

 length of the body; the length of the fin is 

 two thirds of its height. 



The anal arises posterior to the termination 

 of the dorsal, but not so tar hack as the rays 

 of that tin read) when depressed. Its height 

 and length are both a little less than tin 

 the dorsal. 



The ventral* arise a very little it) advance 

 of the dorsal; their height equals the depth 

 ol the body at the caudal liu. 



The pectorals are rounded, equalling the 

 ventrals in height. 



Caudal fin concave, the height of the out- 

 er rays very nearly equalling the length of the 

 head. 



I). 1-8; A. 2-8; V. 1-9; P. 16; C. 19, with 

 eight accessoi ies. 



Seal* i rather lame, about fifty seven along 

 tin' lateral line, and ten ill an oblique low 

 above it at the origin of the dorsal tin. The 

 ~'-.i les are largest ;it about the middle of the 

 side. 



CoJor greenish brown above, lighter on tin- 

 sides, silvery beneath; opercular pieces ting- 

 I ed with purple, all paitsoi th>' fisb clouded 



