226 THE VOYAGE OF H.M.S. CHALLENGER. 



I was able to procure several small fragments of this original specimen, and the results of 

 my investigation seem to warrant me in amplifying the specific diagnosis of Hyalonema 

 limtanicum. From my own notes and from some subsequent observations which Mr. 

 Ridley was kind enougli to make for me, the length of the much damaged body is 12 

 cm., the breadth only 27. The much twisted basal tuft of spicules has a breadth of 

 15 mm. The Palythoa crust is not present having been probably separated off. 



In the absence of a marginal fringe and of the probably originally present terminal 

 sieve-net, it is impossible to determine whether the tuft of spicules, projecting for about 

 1 cm. on the upper end, and doubtless representing a damaged conus, really projected in 

 the intact form. 



Another form in the British Museum, which is said to have been brought from Porto 

 Rico, exhibits a body transversely truncated above, with a well-developed terminal sieve- 

 net, and with an indication of the conus centralis. The basal tuft here attains a length of 

 2G cm. and is covered with the Palythoa crust. Whether this second specimen really 

 belongs to Bocage's Hyalonema lusitanicum, I am not able to determine, since I have not 

 been able to analyse the structure of its component spicules. 



The following description of the skeleton refers only to the first mentioned original 

 specimen of Hyalonema lusitanicum, Bocage. 



The supporting spicules of the parenchyma consist for the most part of diacts of 

 variable size and thickness. These are somewhat pointed at either end, and usually 

 exhibit a simple, spindle-shaped, perfectly smooth course, or occasionally bear a single 

 tubercle, or there may be four or two, projecting from the middle point. They are generally 

 somewhat curved, though frequently perfectly straight. Between these diacts medium - 

 sized oxyhexacts occur, though on the whole not very abundantly. They exhibit six 

 simple, somewhat pointed, straight and smooth rays, which are generally of equal 

 length. Sometimes, however, four rays cruciately disposed are of uniform length, while 

 the other two lying in the third axis, that is to say, radially disposed, are somewhat 

 longer. I also found isolated monacts witlt one end thickened into a knob or rounded 

 off like a button, while the other ended in a point. Scattered through the whole 

 parenchyma in relative abundance there are small, smooth or slightly roughened 

 oxyhexacts, with raj^s which are seldom perfectly straight (PL XXVIII. fig. 16), but 

 usually bent in the familiar fashion, so that three approach each other, and the three 

 antipodals likewise (PI. XXVIII. fig. 15). 



The middle-sized hypodermal oxypentacts which serve to support the skin are quite 

 smooth, their rays run terminally to a somewhat marked point. The autodermal pentact 

 pinuli, which are usually inserted on the latter, bear four short, strongly developed, tan- 

 gential basal rays, with blunt, slightly toothed ends, and a strong distal, about 0"3 mm. in 

 length, which has an almost bushy appearance due to the long lateral processes (PI. XXVIII. 

 fig. 17). The majority of the numerous, radially disposed, dermal amphidiscs have a 



