PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 225 



for the purpose, tlie preparation oug^ht to be allowed to become thor- 

 oughly saturated with the oil of turpentine; the time which it will take 

 to do this will of course depend upon the size and thickness of the ob- 

 ject treated. Tlie principle nivolved in this method is the same as that 

 applied in making balsam or damar preparations on slips for the micro- 

 scope, onlj' that after dehydration is effected oil of cloves is used to 

 make the object transparent instead of turpentine, although the latter 

 is also used. The preparation is then covered with a drop of balsam 

 and the cover-glass put on, when you have a specimen that, with a little 

 care, will last a lifetime. The Semper is simply the microscopic method 

 adapted to large objects which could not be mounted upon slides, and 

 I see no reason why they should not be equally as durable as micro- 

 scopical balsam preparations. It is equally important that the strong 

 alcohol should completely saturate the specimen, else the turpentine 

 will not find its way into all parts of it so as to render it indestructibhi 

 when dry. Two or three hours would probably suffice for the saturation 

 with alcohol or turpentine of moderately large specimens. The harden- 

 ing in the chromic acid solution would require from 12 to 24 hours, 

 according to the size of the object. This method is also free from the 

 objection which applies to Wickersheimer's, that there are no corrosive 

 metallic poisons used. 



By placing the vessel containing the preparation as immersed under 

 an air pump, the penetration of the liquids will be facilitated. 



NOTES OX A COIiliECTIOIV OF FISHES, MADE BV I.IKITT. IIEXKY K. 



1VICE50H.S, IJ. S. IV., ON TBaE ^VEST COAST OF MEXICO, UITH DE- 

 SCRIP riONS OF NEW SPECIES. 



By DAVID S. JORDAN and CMARI.ES H. OIlLB£RT. 



During the autumn of 1880 a cruise along the west coast of Mexico 

 and Central America was made by the U. S. Coast and Geodetic steamer 

 Hassler. Lieut. Henry E. Nichols, the officer in command, took much 

 pains to make collections of fishes whenever they were obtainable. As 

 a result of his labors we have the small but extremely valuable collec- 

 tion noticed in the present paper. It will be observed that twelve of 

 the specimens came from the Eevillagigedo Islands, in the open sea to 

 the westward of Mexico, a locality where no collections of fishes had 

 been previously made by any one. Six of these specimens belong to 

 species new to the fauna of Noith America. 



We give an enumeration by localities of the species in the entire col- 

 lection, with the number borne by each specimen on the records of the 

 United States National Museum. 



A. — Whaler''s Bmj, Guadalupe Island, Lotcer California. 



1. PsEUDOJULis 3I0DESTUS (Girard) Gthr. 



2. PsKUDOJULis MODESTUS (Grd.) Gthr. (No. 28,301 U. S. Nat. Mus.) 



Troc. Nat. Mus. 81 15 Dec. S4, 1881. 



