Verrill, Notes on Radiata. 289 



small, roughly granulated spines (some of which also occur among 

 the lateral spines), and an imperfect median row of large, distant 

 ones, like those of the sides, but somewhat smaller. The entire sur- 

 face, between the spines, is covered with coarse, rough granules. 

 Madreporic plate subcentral, small, narrow, elongated, composed of 

 a few radiating lamellse. Color, in alcohol, reddish brown. 



Panama, — F. H. Bi-adley. One specimen, at low-water of spring 

 tides, on rocks.* 



This species is interesting as showing the propriety of retaining 

 Gray's genus Mithrodia, which was established to receive 31. spinii- 

 losa (Linck. sp.) and If. clavigera (Lamarck sp.). The former is said 

 to be an Asteracanthion by Mtlller and Troschel, and the latter seems 

 to be but little known. For these reasons the necessity of retaining 

 this genus has been doubted by some authors. The present species, 

 however, which agrees well with the characters assigned by Gray, 

 and must be closely allied to 31. clavigera.,\ cannot, with propriety, 

 be united to any other genus. It is not at all allied to Asterias 

 {Asteracanthion M. and Tr.), but approaches more nearly to Ophidi- 

 aster and allied genera. The ambulacral pores are large and form 

 but two rows. 



Heliaster helianthus Gray. 



Asterias lielianthus'Lixmarc^] Blainville, Actinologie, tab. 23, fig. 5. 



Asterias {Heliaster) helianthus Gray, Ann. and Mag. N. H., 1st series, vi, p. 180, 1840. 



Asteracanthion helianthus Miill. and Tr., Syst., p. 18, 1812. 



Numerous specimens of this species, both large and small, were 

 sent from Callao, and a few from Paita, Peru, by Mr. Bradley, a part 

 preserved in alcohol and a part dried. It occurs, also, at Caldera, 

 Chili,— Capt. W. H. A. Putnam (Coll. Essex Institute). It is found on 

 rocks at low-water, adhering very firmly. 



Disk broad, rays short, slender, about thirty or thirty-five. Kadii 

 as 8 : 5. A medium-sized specimen measures from center to end of 

 rays 4 inches ; to edge of disk 2-5 ; length of rays beyond disk varia- 

 ble, longest about 1 '5. 



. The interambulacral plates bear a single row of rather long, stout, 

 blunt spines, one to each plate, a large and small one often alternat- 

 ing ; outside of these, but near them, the ventral plates bear about 



* Two specimens have since been sent from La Paz, by J. Pedersen, — Eepriut. 



f Another species of this genus, with remarkably long arms, which must be nearly 

 allied to the M. clavigera, was collected at the Sandwich Islands by Mr. Horace Mann, 

 and by him presented to the Boston Society of Natural History. 



