248 bulletin: museum of comparative zoology. 



Off Diamond Head, Oahu, 27-28 fathoms. 

 Off Diamond Head, Oahu, 27-29 fathoms. 

 Off Diamond Head, Oahu, 28-29 fathoms. 

 Off Diamond Head, Oahu, 14-28 fathoms. 

 Off Kauhola Light, Hawaii, 24-83 fathoms. 

 Off Hanamaulu, Kauai, 68-253 fathoms. 

 Off Modu Manu, 23-26 fathoms. 

 Off Modu Manu, 26-33 fathoms. 

 Off Modu Manu, 71-160 fathoms. 

 Off Modu Manu, 20-30 fathoms. ■ 

 Off Modu Manu, 40-56 fathoms. 

 One hundred and seventy-three specimens. 



Clypeaster lytopetalus A. Ag. and Clark. 



This species may be recognized at once by its small size and general resem- 

 blance to scutiformis, combined with short, broadly obovate petals, the anterior 

 one widely open, and with a deep groove in each ambulacrum along the median 

 suture, extending from the abactinal system nearly to the actinostome. The 

 tubercles are less numerous than in scutiformis and the primary tubercles contrast 

 decidedly with the miliaries. The poriferous zones are exceedingly narrow (less 

 than one millimeter in width), and are of unequal length in the lateral petals. 

 The sutures between the abactinal plates are quite distinct. The genital openings 

 are very small. The test is very thin and the internal structure is remarkable for 

 the great scarcity of pillars, of which there are one or two stout ones and one or 

 two slender ones in each interradius, nearer the actinostome than the margin of 

 the test; there are no needle-like internal projections such as are abundant in 

 scutiformis. The larger specimen (St. 3962) is 33 mm. long, 26 mm. wide and 



10 mm. high. The test is decidedly arched, with a deeply sunken actinostome, 

 and is 5 mm. thick at the margin. The odd and the posterior petals are about 



11 mm. long and 5-6 mm. broad near the tip, while the anterior lateral petals 

 are equally broad, but only 8 mm. long. The odd petal has the poriferous zones 

 3 mm. apart at their distal ends. The color is dark yellowish-brown. The 

 smaller specimen is about half as large and is bright reddish-brown. It is not 

 impossible that this species will prove to be the young of C. excelsior Doderlein, 

 from Japan, but the remarkable appearance of the petals distinguishes it from the 

 only specimen of that species yet known. 



Station 3936. Off Laysan Island, 79-130 fathoms. 



3962. Off Laysan Island, 16 fathoms. 

 Two specimens. 



Clypeaster leptostracon A. Ag. and Clark. 



This species is nearly allied to C. virescens Doderlein from Japan, but differs in 

 the outline of the test, the very narrow poriferous zones, the arrangement of the 



