PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 117 



NOTE OIV THE OCCimREIVCE OF A SII>VER IiAMPBEY, ICIITHY- 

 OMYZOIV OASTAIVEUS, OIRARD, IIV t,OUISIANA. 



By TAKJLETON H. BEAN. 



Nearly two years ago Mr. N. B. Moore, of Forlorn Hope, Louisiana, 

 sent to the National Museum, at the request of tlie Director, a lamprey 

 which he perceived to be difierent from the sea-lamprey [Fciromyzon 

 americamis^ = marimis), by comparing it with a description in ZelFs 

 Encyclopedia. About that time the writer was on his way to Alaska, 

 and had no opportunity to examine the specimen forwarded by Mr. 

 Moore. It was placed in storage and came to my notice again only a 

 few days ago. As this individual shows some unusual characters, it is 

 worth while to call attention to them. It agrees pretty well with the ac- 

 couht of the species described by Girard from Galena, Minn., under the 

 name Iclithyomyzon casfcnwus, but shows a variation from the ascribed 

 characters of the genus in having three close-set maxillary teeth, while 

 some of the lateral teeth are bicuspid. 



I insert here Mr. Moore's description of the recent specimen : 



" I have a lamprey — first ever seen by me, and identified by a descrip- 

 tion in Zell's Cyclopiedia. Thinking it quite far south for one of this 

 species — Petromyzon amcricauus, if it be this one — I put it in whisky, 

 and, as I found it to differ from that given in Zell in one particular, the 

 dorsal fin being 4^- (inches) in length, continuous, not separated, I 

 thought you would like to examine it. If so, I will send it to you. 

 Total length, 9f inches ; anus to tip of tail fin, 2 ; between anterior and 

 posterior gills, 1^; tip of snout to anterior gill, 1^; commissure of 

 mouth, 2; greatest depth of lish at interior part of dorsal, |; greatest- 

 width 2 (inches) from tip of snout, ^ ; thence a true taper to tip of tail 

 in lateral outline; body not cylindrical. Color ochraceous about head, 

 then yelloAvish gray; small blue dots from head to tail and on under 

 side of neck." 



For convenience of comparison, I copy here Girard's description ot 

 I. castaneus*: 



" Spec. Char.— Head depressed, constituting the ninth of the total 

 length ; body and tail compressed. Buccal disk sub-elliptical, provided 

 with a double series of short, tentacular fringes upon its periphery. 

 Posterior margin of buccal aperture exhibiting a series of nine teeth, 

 disposed upon an arc of a circle. Eyes small and inconspicuous; 

 spiracle sub-tubular, raised above the surface of the head. Origin of 

 the dorsal fin equidistant between the anterior margin of the buccal 

 disk and the apex of the tail. Vent situated immediately in advance of 

 the most elevated portion of the dorsal fin. Chestnut-colored, of a 

 darker tint above than beneath, 



*<Rep. U. S. Pacific R. R. Surv., Fishes, 1858, pp. dtil-^. 



