158 



'ENDEAVOUR" SCIENTIFIC RESULTS. 



The dermal skeleton consists of acanthostyles and oxea. 

 The proportion in which each occurs is variable, but the 

 smooth spicules are always present, and in places — particu- 

 larly where the membrane overlies large subdermal spaces — 

 are more numerous than the spined spicules. Occasionally, 

 over small areas, an approach to the reticulate arrangement is 

 met with ; or the acanthostyles may be clustered in small 

 patches so as to give a mottled appearance, but there is never 

 (in any observed case) a parallel arrangement of spicules to 

 form the sides of meshes of a distinct reticulation such as is 

 found in the varieties arenacea and levis. 



Fig. 29— ('. /■«- 

 crustans var. di- 

 gitaia. a Oxea 

 (showing the ex- 

 treme of asyui- 

 metry in these 

 spicules), b Iso- 

 chela arcuata. 



Megascleres. — 



(i.) The oxea vary in length from i6o to 

 J JO /( ; the stoutest are probably 

 never more than 4.5 j( in diameter. 

 The characteristic end-flexure is 

 only of occasional occurrence, it 

 may, however, be developed quite as 

 highly as in any of the other 

 varieties, as the spicule shown in 

 Text-figure 29 bears witness. The 

 oxea are characterised in compari- 

 son with those of the other varieties 

 by a slight elongated subterminal 

 constriction which occurs at both 

 ends. In this respect the spicules 

 resemble those of Clathrissa arhus- 

 ciihi. The feature is occasionally 

 obser\ ed in the spicules of some of 

 the other xarieties of Crella incnis- 

 tcnis but is never so well marked as 

 in the present one. 



(ii.) The principal acanthostyles reach a 

 maximum size of 170 x 9 ;(. 



'iii.) The dermal acanthost}les \ar} m 

 length from 60 to 90 j< ; the stoutest 

 are 7 or <S /( in diameter. Very rarely acanthoxea are 

 met with in the dermal skeleton ; these are sometimes 

 over 100 ji in length. 



Microscleres. — 



The chela?, which vary in length from 13 to .'0.5 ;/, but are 



rarelv more than iS /<, show a scarcely appreciable 



differentiation into two forms. 



As alreadv pointed out this variety is probably identical w ith 



the tvpical variety which comes from Port Phillip. But there 



