42 PROCEEDINGS OF THE NATIONAL MUSEUM vol.81 



terminal disk are arranged in a spiral manner and are not so 

 regular as in those of the larger ones. 



In the hypodermal and hypogastral layers, the prominent tylo- 

 hexasters (fig. 6, g^ A, ^) are abundant but are not so numerous in 

 the parenchyme, being sparsely distributed, intermingled with 

 discohexasters derived by reduction and stoutness of terminals from 

 the former. The tylohexaster of large rosettes, which possess term- 

 inal rays bearing pinheadlike disks at the ends, exhibits the typical 

 number of principal rays, since as a rule six are present. At the 

 slightly expanded outer end they divide into 6 to 15 straight or some- 

 what S-shaped terminals, which diverge slightly in a tuft and attain 

 a length about double that of the principals. Each terminal, 

 smoothed on the surface, bears at its extremity a small pinheadlike 

 disk. The tylohexasters vary considerably in size, measuring SO/a to 

 150/A in diameter ; the larger ones occur mostly in the ectosome, while 

 the smaller ones are present in the choanosome. Two other kinds of 

 spicules, which are considered derivatives of the normal tylohexas- 

 ter above mentioned, are found rarely in the parenchyme. I there- 

 fore do not give special descriptions of them. 



Frequently I have found a discohexaster (fig. 6, j) intermingled 

 with the tylohexasters, mostly in the ectosome, with 3 to 4 robust 

 gently curved terminal rays. The curvature of the terminal rays 

 usually assumes an S-shaped form and results in the formation of 

 strong, three or four rayed perianthlike whorls at the end of the 

 principal rays. 



Uncinates of heHngiana usually penetrate the dermal surface 

 obliquely, though they are sometimes perpendicular to it. They 

 vary in length and thickness, measuring 1 mm to 1.5 mm long and 8/* 

 broad at the center, and are surrounded by fine barbs. 



The large diactins (fig. 6, ^, I) in the hypodermal regions show a 

 character peculiarly different from those of other members of the 

 genus. They may attain a length of 9 mm, measuring TO/x, broad at 

 the center and gradually attenuating to a conically pointed end. 

 The entire surface of the spicule is nearly smooth, except at both ends 

 where the surface is sparsely roughened by microspines, though that 

 of the larger one is distinguished by larger and more densely dis- 

 tributed microtubercles. 



INDETERMINABLE FARREA 



There is in the collection a small colony of specimens of Farrea 

 collected by the Albati'oss and not determinable specifically. It is 

 completely macerated and as it would be futile to describe it in detail, 

 I merely give the following record of it : 



Station 4768 ("Bowers Bank," Bering Sea). Small macerated 

 colony. 



