88 ' SEVENTH REPORT. 



to the above interpretation. That the pull alone on other organs or 

 parts of the body will not usually make the animal turn, I found by 

 inserting small pieces of soft iron, silver-plated for the purpose, in 

 various parts of the dorsal region of the body. Later, also, I cemented 

 such pieces to the antennules. There was ordinarily no response until 

 the pull of the magnet was sufficient to tend to unbalance the animal, 

 and then the response was somewhat similar to that obtained when 

 there were iron-filings in the otocysts. 



It has been stated that the palaemonetes as well as other cursta- 

 ceae when freshly moulted are unable to orient properly on account of 

 the loss of otoliths. But it must be remembered that just at this time 

 their hard exoskeleton, the firm attachment for the muscles, has been 

 removed.^ Virbius, a crustacean which is permanently in a soft con- 

 dition, is of rather unsteady motion. In this animal there are no 

 otocyst organs present and this is said to account for its acrobatic 

 feats.- But these are no less remarkable than those of Gammarus. 



Mysis was next operated on. After some attempts to unbalance the 

 animal by removing the segment of the tail fin containing the otocyst 

 organs, the whole fin was removed. The animals kept their up and 

 down position very well and a few of them turned over and over as 

 has been described by others. Now when we remember that the tail 

 fin of these little crustaceae is their chief rudder, I believe we are safe 

 in saying that Mysis is not much dependent on its otocyst organs, when 

 the loss of both these and the rudder causes only unsteady motion, not 

 a serious unbalancing as to the vertical. 



Detroit, Mich., April, 1905. 



THE STATUS OF EUTAENIA BRACHYSTOMA. 



C. C. WHITTAKER. 



Mr. Ruthven in his paper on "Butler's Garter Snake" (Biol. Bulle- 

 tin, Yol. VII, No. 5, Nov., 1904) after mentioning the fact that the 

 only specimen of hrachy stoma is in the collection of the Philadelphia 

 Academy of Natural Sciences, quotes A. E. Brown as saying that 

 "there is little ground for thinking this specimen other than a dwarfed 

 E &irtalis sirtalisJ" Ruthven then continues "After a comparison with 

 the specimens of E hutlerii from here Mr. Brown writes me 'I have 

 re-examined the type of E hrachystoma Cope, and still find no reason 

 to believe it other than an anomalous E sirtalis sirtalis.' Cope says 'it 

 is small but not young.' I myself see no way to determine this, it 

 may or it may not be so. The specimen was about ready to shed when 

 he got it, which, of course, obscured the pattern. I cannot think it 

 the same as E hutlcriV " Mr. Ruthven apparently accepts this as final 

 for he goes on to the discussion of the difference between hutlerii and 

 E vagrans without remark. This treatment seems somewhat summary 

 in view of the fact that Cope's descriptions of 'brachystoma and butlerii 



1, 2 Prentiss discusses both cases but the view he presents seems to me not proved. 



