VerrllL, Note^ on Jladlata, 441 



•350, -775 by -300, '750 by -350, -750 by -325, '725 by '300, *726 by -275, 

 •700 by -275, -675 by -325, -650 by -300, -625 by -325, -625 by '300, -625 

 by -225, -600 by -325, '600 by -250, -600 by '225, '575 by '325, -575 by 

 •275, -550 by "275, '500 by '200, -450 by -225, '425 by -300, "400 by '225; 

 the irregular flattened spicula -700 by -326, '625 by -475,, '625 by -275, 

 •575 by -400, -550 by -450, -525 by -400, -525 by -375, '475 by '375, -450 

 by ^325, -425 by -425 ; the heads -425 by '300, -250 by -200 ; the small 

 spindles -4^5 by -150, -400 by -100, -400 by -087, "375 by -150, -300 

 by •125. Some spindles from the vermes are included among the 

 preceding measurements of larger spindles, others measure '825 by 

 •250, -800 by '200, "775 by '102, '625 by -200, '625 by •175. 



Panama and Pearl Islands, common in rocky pools near low-water 

 mark, — F. H. Bradley; Acapulco, — A. Agassiz; Corinto, — J. A. 

 McNiel. 



This species is liable to be confounded with the young of M. aus- 

 tera and 31. nlhida^ and perhaps other species ; from the latter it dif- 

 fers in color and in having smaller verrucse ; from the former in its less 

 projecting, more appressed and smaller verrucae, and lower growth, as 

 well as lighter color ; and from both it differs widely in its much smal- 

 ler and very differently shaped spicula, w^hich more nearly resemble 

 those of M. rohusta aud M. purpurea. From the last it may be at 

 once distinguished by its color and less oppressed verruca?, which are 

 much rougher, owing to the projecting points of the more acute spic- 

 ula ; from the former it differs in its well developed verrcua?, smaller 

 cells opening upw^ard, lower growth, and less robust branches. 



Muricea purpurea VerriU. 



JTuricea hebes {pars) Yerrill, Bulletin Museum Comp. Zool., p. 36, 1864. 

 Muricea purpurea VerrOl, American Jour. Science, vol. xlv, p. 412, May, 1868. 



Plate VII, figure 6. Plate VIII, figure 12. 



Corallum sparingly dichotomous, with stout, obtuse, rigid, mostly 

 curved branches, usually arranged nearly in one plane, closely covered 

 by small, appressed, granulous verrucje. 



When young it often rises to the height of 2 to 4 inches as an up- 

 right, simple, clavate stem, "25 to '32 inch in diameter. Other specimens 

 are two or three times dichotomous before they become two inches high. 

 The larger specimens, when well developed, usually consist of several 

 trunks arising near together from a broad, expanded Ijase, forming 

 open clumps of stout, crooked branches, which are sparingly divided, 

 the branchlets upon each main stem generally spreading nearly in one 

 plane. The trunk often forks within half an inch from the base, but 



