T4 



06' N., long. 1130 02' W.; and the pectoral fins of E. 

 volitaus, Bl., from the Atlantic. 



Dr. Eckel presented, for the library, a copy of 

 Knapp's Chemical Technology. 



Oct. 1, 1855. 



Col Ransom in the chair. 



Donations to the Cabinet) 



From Mr. D. E. Hough, of Oakland, a specimen of 

 the Barn Owl [S, pratincold), and one of the Gopher 

 Snake (Pituophu eatenifer). 



From Col. L. Ransom, a series of specimens of Ja- 

 panese manufacture. 



From Dr. Lanszweert, a specimen belonging to the 

 genus Leucosticte. 



From Dr. H. Behr, insects of the genus Myrmeleon. 



Sax Francisco, Oct. 8th, 1855. 



Dr. Randall in the Chair. 



Donations to the Cabinet. 



From Mr. Hough, of Oakland, a specimen of Rat- 

 tlesnake (Crotalus,) and one of Eutainia ordinoides; 

 also, one of Nuttall's Whiproorwill (C. J\uttallii 

 Awl.) 



From Dr. Gibelin Du Py, two skulls of Albatrosses, 

 D. exulans, L. and D. chlororynchus, Gm., from 

 the vicinity of Cape Horn ; for which the thanks of 

 the Academy were voted. 



From Dr. Ayres, two skulls of the Violet Green 

 Cormorant {P. resplendent, Aud.) and one of the 

 Western Gull (L. oceidentalis, And.) from the Far- 

 rallon Islands. 



From Dr. Lansweert, specimens of Diadophis 

 amabilis, Ophibolus Boylii, and Pituophis eate- 

 nifer, from this vicinity. 



Mr. J. B. Russell presented for the Library, Swain- 

 son's Natural History and Classification of Birds, 

 two volumes. Mr. Russell also deposited a New 

 Zealand Axe, made of an extremely hard serpentine 



rock. 



Dr. Win. 0. Ayres exhibited a specimen of a Shark, 



of a new generic type, with the following description : 



NOTOBTNCHUa MACCI.ATUS — AyrCP. 



Form much elongated, depressed anteriorly, then 

 rounded, compressed posteriorly. Head broad, flat- 

 rened above ; snout widely rounded, yet having a 

 somewhat salient projection in the median line with 

 a shallow emargi nation on each side, corresponding 

 to the situation of the nostrils. Greatest depth about 

 one eighth the total length ; depth of the head, at the 

 eyes, a little more than half the greatest depth, which 

 latter is equal to the breadth of the head at the line 

 of the spiracles. 



Branchial apertures seoen on each side, quite large, 

 the posterior one situated just atterior to the base of 

 the pc-ctoral fia. They are of such size as to be very 

 mmifest when the fish is viewed from either the dor- 

 sal or the ventral surface ; the anterior ones equal 

 about one- third tht* depth of the head at the eyes. 



Spiracles small, nearly equidistant from the eyes 

 anl the branchial apertures, being a little nearer the 

 ra;lian line than the eyes are. Their diameter is not 

 more than one-sixth of that of the eye. 



Nostrils almost terminal. They are situated in 

 the emargination of the anterior border of the snout, 

 but placed so much beneath as not to be visible, 

 viewing from above. Each nostril is double, as in 

 ordinary osseous fishes, the two apertures being sepa- 

 rated by a strong transverse septum. Each aperture 

 is oval, somewhat larger than the spiracles ; the an- 

 terior aperture has a slight lobule on its axtero-pos- 

 terior border. 



Mouth very large, occupying the entire breadth of 

 the inferior surface of the head ; its anterior border 

 a little in advance of the anterior line of the eye, the 

 distance when the jaws are closed being equal from 

 this point to the tip of the snout and to the posterior 

 angle of the mouth. Teeth of the lower jaw large, 

 few. (about seven or eight on each side of the median 

 line,) flat, arcuated and very coarsely serrated on 

 the cutting edge, the serrations pointing outward. 

 This row of teeth, behind which as usual lie other 

 rows concealed, forms a line almost like the continu- 

 ous edge of a knife. The teeth of the upper jaw are 

 about equal in number to thone of the lower, but of 

 different form. Those of the centre are narrow, 

 acute, without denticles at the base but with minute 

 teeth anterior to them ; those next exterior are a lit- 

 tle broader at the base, with denticles , exterior to 

 these they become broadly triangular, the inner bor- 

 der entirely smooth but with its line continued so as 

 to form a very sharp point directed outward, below 

 which are one or two other serrations on the outer 

 bonier ; the external teeth of all approach in form 

 those of the lower jaw. 



A lateral line can be traced with entire distinct- 

 ness, extending from the head nearly to the tip of the 

 tail, at first along the upper portion of the side, then 

 becoming lower, until along the tail it is below the 

 middle. 



The eye* are on the side of the head, elliptical, dis- 

 tant from the tip of the s. out, not quite three times 

 their own longitudinal diameter. 



The dorsal fin is single. It arises a little nearer to 

 the snout than to the tip of the tail. It is rhomboidal, 

 its height anteriorly (which is somewhat greater 

 than its length) being about three fourths of the 

 greatest depth of the fish. The posterior border is 

 net closely applied to the back, as in many sharks, 

 but rises obliquely as in most osseous fishes. The 

 upper border is concave 



The pectoral fins are rhomboidal, broad, their 

 height anteriorly equal to the depth of the fish, and 

 not quite equal to the distance of their origin from 

 the tip of the snout. 



The ventral fins terminate on the plane of the com- 

 mencement of the dorsal, which fin they equal in 

 length. 



The anal fin, which is small, arises just anterior 

 to the termination of the dorsal. 



The tail is very long, more than one- third the 

 length of the fish, slender, its separation from the 

 back marked by n decided though not deep depres- 

 sion. The fin is almost wholly beneath, a very small 

 continuation of it around the last vertebras being 

 discernible, ft is highest in front, not quite equal- 

 ling the height of the dorsal, becomes gradually low- 

 er, and a short distance anterior to its termination 

 rieos again, forming a distinct triangular lobe. 



Color dark bluish trray above, with numerous, 

 sm til, irregular hlack blotches ; lifjl ter beneath. 



The Shark here described presents certainly a very 

 singular grouping of characters. The only genus 

 with which itcan be compared is Gavicr'aJVotidunns, 

 previously separated by R ifinesque under the name 

 Heptranchias, both founded on Lnccpede's Squalui 

 cinrrevs. With this our type agrees in the remark- 



