VerriU.] 382 [April 7, 



this species. The larger one has almost exactly the same size and 

 outline as the specimen figured. It is therefore probable that the 

 locality given ("Australia?") is erroneous. 



Perhaps A. ovulum Llitk, is only the young of this species, although 

 more oblong in form. 



The larger specimen is 1.70 inches long; 1.55 broad; 1.25 high. 

 The smaller one 1.50 long; 1.35 broad ; 1.05 high. 



Brissus obesus VerriU. 



Transactions Connecticut Academy, Vol. I, p. 316, 1867. 



A larger specimen, with part of its spines, has been received from 

 Capt. Pedersen, collected at La Paz. It agrees well in form and 

 other characters with the original specimens. The spines are silvery 

 white and slender, oa the upper side decreasing regularly in length 

 from the peripetalous fasciole to the margin; the upper ones being 

 .10 or .12 long, the lower ones .25 to .28. Those near the margin 

 beneath are quite long, .35 to .38, those near the mouth largest. 

 This specimen is 2.65 inches long; 2 broad; 1.40 high. 



Desoria nodosa VerriU, sp. nov. 



Irregularly broad oval, subangulated ; the anterior end deeply 

 emarginate; the posterior truncate, slightly oblique, a little concave 

 below the anal area. On each of the four, lateral, interambulacral 

 regions of the upper surface are two radiating series of distant, 

 slightly elevated, nodular elevations or ridges, which give the surface 

 an irregular appearance, and by their continuation downward to the 

 lower surface, give a somewhat angular appearance to the margin. 



Posterior interambulacrum elevated in the middle, with a series of 

 three or four slightly raised nodes. Tubercles of the upper surface 

 small and nearly uniform, except on each side of the anterior ambula- 

 cral furrow, where there are several irregular rows of larger ones, 

 about equal in size to those near the margin on the lower surface. 

 Anterior ambulacrum considerably depressed, with a row of double 

 pores on each side, which extend to the mouth. Anterior lateral am- 

 bulacra more sunken, narrow, elongate, the end curved forward ; pos- 

 terior lateral ambulacra scarcely shorter, narrow, elongated, the outer 

 ends considerably curved and divergent, the inner portion suddenly 

 narrowed, and with minute pores, as in the anterior pair. Ovarial 

 openings four, rather large, the posterior.jiair a little larger and farther 

 apart, the madreporic plate extending between them. Peripetalous 

 fasciole angular and sinuous, each angle situated on one of the 

 prominences or nodes in the interambulaci-a. In the posterior inter- 



