140 



aquatic mn 



The habits of these Mud Minnows, 

 especially those of U. pygmaea, in na- 

 ture and in aquaria, have been quite fully 

 described in the articles cited above by 

 Doctor Gill and Doctor Bean; they 

 agree with my own observations, and 

 they are surely quite remarkable. In- 

 deed, the European Umbra (dogfish) 

 was described as early as 1726 (Mar- 

 sigli), and again in 1756 (Kramer), 

 while a great many naturalists have re- 

 ferred to these fishes since, the best 

 known account having been rendered by 

 Heckel and Kner (1858), C. C. Abbott 

 (1884), L. Kathariner (1899), and 

 others. See also "Fishes of Illinois," 

 Forbes and Richardson, pp. 203-205. 



There is one point worthy of notice 

 here that will, in part, account for the 

 remarkable differences to be found in 

 the descriptions of the external colora- 

 tion of the Eastern Mud Minnow given 

 by the authors mentioned above. In the 

 first place, the fish changes its coloration 

 to a wonderful degree when placed in 

 alcohol and other preservative fluids. 

 Then, in life, the fully adult specimens 

 (4 to 4^2 inches long) — the young ones, 

 too — change their color to such an extent 

 as to appear like an entirely different 

 fish ; this is particularly true of Umbra 

 pygmaea. The changes are due to causes 

 similar to those that produce them in 

 some lizards, as Anolis, or any of the 

 chameleons. Sometimes it will be of a 

 deep umber brown, with all the markings 

 in strong relief ; when, again, it will 

 have a general color of a pale clay tint, 

 with all the markings, or most of them, 

 still more in evidence. These facts 

 should be borne in mind, and I have 

 failed to find them stated in any of the 

 accounts I have read of the fish. 



As stated above, at the U. S. National 

 Museum I examined many specimens of 

 Umbra umbra, U. limi, and U. pygmaea, 

 and among the last named Nos. 16,896 



(Trib. Chesapeake Bay) ; 72,442 (one 

 large, one small, Laurel, Md.) ; 27,481 

 (Eastern Maryland) ; 68,321 (Long 

 Island, N. Y., 6 specimens) ; 35,971 (E. 

 Lake Patchoque, L. I., 1 large, 4 juv.) ; 

 67,455 (Laurel, Md., 2 specimens), and 

 60,797 (pool near Chain Bridge, D. C.) 

 Some of these specimens agreed, in the 

 main, with the figure and description of 

 Umbra pygmaea as given by Jordan and 

 Evermann, while others by no means did. 

 It would seem that all collectors and de- 

 scribes of the Eastern Mud Minnow 

 have, for more than a century, been so 

 thoroughly satisfied that we find but one 

 species of Umbra in the Eastern United 

 States, that every one taken has been 

 referred to it, whether it agreed with 

 published descriptions of that species or 

 not. 



Now the larger specimen of the two 

 in 72,442 of the above list has a length 

 of 8.2 cms. ; it is marked like one living 

 in one of my aquaria — that is, the longi- 

 tudinal stripes are practically absent. 

 There is a single, whitish stripe running 

 the entire length on either side, mesially ; 

 the general color is a rather pale clay 

 brown, distinctly mottled with dark 

 brown on the back. There are dark 

 markings on the side of the head — one 

 heavy one through the eye and one be- 

 low it; chin very light. D. 14; A. 9. 

 This specimen hardly agrees in a single 

 particular with Jordan and Evermamrs 

 description of U. pygmaea. This is also 

 true of No. 68,321 (the largest specimen, 

 also largely so the smaller ones). It has 

 a length of 7 cms., and is not markedly 

 striped, while the above described whit- 

 ish stripe is conspicuous; chin pale gray. 

 D. 14; A. 8. No. 60,797, length 10 cms., 

 caudal spot white, bordered with black ; 

 mid-lateral longitudinal stripe white ; 

 chin pale gray. D. I. 14 ; A. 8. An- 

 other specimen, or rath A r two specimens, 

 Continued on page 14/. 



