320 Verrill, Notes on liacUata. 



end, where the subanal fasciole crosses it, and at the mouth. Pores 

 around the mouth large, in five conspicuous rays. The spines are 

 long and slender on the lower surface, short and fine above, except 

 on the borders of the ambulacra and within the fasciole, where the 

 tubercles are considerably larger. 



Color of test dark ash-brown, a yellowish white line or narrow 

 band passing from the ambulacral petals or rays to the outer margin, 

 along each border of the ambulacral zones. Color of spines very 

 dark gray, or blackish, 



A small specimen from Cape St, Lucas is 1"55 inches long; 14 

 broad; "88 high ; from center to end of anterior ambulacral rays •52 

 of posterior '57; width of latter -12; center to anterior end 1-7 

 to posterior end rs ; length of area within subanal fasciole '4 

 breadth •45. 



In form this agrees nearly with the large specimen, except that the 

 posterior interambulacral region is depressed within the peripetalous 

 fasciole and the lower surface is more convex, the plastron being 

 subcarinated and most prominent in the middle. The anterior, odd 

 ambulacrum is scarcely depressed below the genei'al surface. 



The form of the peripetalous fasciole is the same as in the large 

 specimen. Color of test and spines, in alcohol, is white, the spines 

 transparent. 



Panama Bay, dredged in 6 to 8 fathoms, shelly bottom, — F. H. 

 Bradley. Cape St. Lucas, — J. Xantus (Coll. Smithsonian List,). 



This species is allied to M. Garretii of the Kingsmills Islands, but 

 the latter difiers in having a more elevated and convex form, espe- 

 cially posteriorly ; in having the anterior end high and abruptly de- 

 scending, with the imperfect ambulacrum in a deeper groove ; in 

 having relatively shorter and broader ambulacral rays, which are not 

 so uniform in width, and the posterior ones more curved; in the 

 form of the anal area, which is pointed below, instead of rounded ; 

 in the subanal fasciole, which is smaller, narrower, and more rounded, 

 being about as long as broad. The peripetalous fasciole bends up in 

 an abrupt angle in the lateral interambulacra, instead of crossing in 

 a broad, slightly concave curve. 



AgaSSizia OVUlum Liitken, Viclensk. Medd., p. 134, tab. II, fig. 8, 1864. 



Mr. Bradley sent one specimen of this species, found on the beach 

 at Panama. Dr. Liitken's specimens came from Boccones, Central 

 America, 



