Narkatue of Bahama Expedition. 155 



Monthly Magazine" for Octobi-r, 1893, though my sketches, made on the 

 t^pot, show sharper angles at all the knee joints. The same position is not 

 always maintained, however, by different specimens. 



The movements of a tired specimen were as follows: In making a stroke 

 the middle legs were brought forward until the tips were about on a line 

 with the head. They were tlien rapidly brought back so as to nearly 

 touch the tips of the hind pair, which were moved comparatively but little- 

 The posterior feet seem to be used to steer with rather than as an aid in pro- 

 gression. The four legs work in unison, not alternately, /. c, the middle legs 

 keep time with each other and with the hinder pair. The tips of the legs 

 rest on the water, and are not immersed in it so that the little hollows near 

 each, caused bv the weight of the insect, can plainly be seen. With cap- 

 ti\e specimens sunlight acted as a stimulant, and e\oked acti\ity, which 

 \vas lessened by shade. 



One Ilalohalcs was then placed in a tightly corked bottle, tilled, when 

 ■immersed, so as to make tertain that no air was enclosed, e.Kcept the thin 

 film which invested the insect. This was done at 1:22 p. M., and at 1:30 

 ■was witnessed what was then supposed to be the final struggle with death; 

 .-.ifter the expiration of four minutes this recommenced, and was continued 

 at irregular inter\als until 1:43, after which 'no more were seen until 1 :48_ 

 .^it which time a tin\- bubble of air made its way from the cork, and at j :58 

 -.mother of these bubbles e\oked a feeble struggle, the last. When finally- 

 remo\ed to tlie alcohol bottle, not a movement could be detected, ;ind the 

 insect was undoubtedly drowned. 'Ihis would appear to antagonize the 

 theory that they staj' beneath the surface in stormy weather. I also 

 noticed, with several specimens, that they could (or would?) only dive after 

 being wet so that " skimming" was impossible, but this does not agree with 

 the observations of other naturalists, and I recognize its practical worthless- 

 .ness as purely negative evidence. 



This was by far the lichesl field for Crustacea that we 

 ■encountered during our work. The Brachyura were, as 

 usual, the most abunchmt forms and a never-faihng source of 

 interest to the students, who were constantl}' discovering some 

 grotesque shape or special protective modification. Between 

 forty and fifty species of Braclnura were secured here, hardly 

 a haul coming up without its qu(Aa. This collection will be 

 systematically treated in a forthcoming report by Miss Mary 

 J. Rathbun, of the Smithsonian Institution, and it is to her 

 kindness that the identification of these forms is due. I>v far 

 the greater number belong to the Maioid group, commonh- 

 called ••sea-spiders.'' Three species of Podorficia \\{^yc found, 

 the first, /''. g-raci/ipcs Stm.. having the first true walking leg 

 ver\- o'reatlv lenirthened. beinij about twice as lonij as the 



