22 ARî. 1.— î. iJiMa : hexaOtinelltda, iit. 



unguiculalus) a greater or less number of additional oscula on 

 the lateral wall. The multiplicity af oscules is certainly not a 

 peculiarity of tlie Euplectellidie ; and moreover, cases are not 

 wanting in this family which indicate that we have here to do 

 with a very variable character, sometimes apparently of no more 

 than specific, or at most generic, value, Kevertheless, it seems 

 undeniable as a general fact that the tendency toward that 

 character is, in the Euplectellidte, brought into expression with 

 such a degree of constancy and accentuation as is foreign to any 

 other lyssacine hexasterophorous family (Leucopsacidse, Caulopha- 

 cidic, Rossellidœ). And further, it is a noteworthy feature that on 

 this account the aj^pearance of individuality is not generally in 

 the least impaired. Whereas, in the Caulophacidae, the formation 

 of additional oscula in an individual is always in connection with 

 a ])rocess of budding, thus imparting to it a more or less cormus- 

 like or " polyzoic " appearance. 



4. The dermalia (=F. E. Schulze's Hypodermalia) in the 

 Euplectellidte may be said, as a general matter of course, to 

 still remain in a comparatively incipient stage of morphological 

 ditlerentiation."" Thus, they stand in direct and intimate relation 

 with the parenchymalia in that the proximal ray dips right into 

 the choanosome ; they are known in some cases even to intergi'ade 

 in the characters of rays with certain hexactinic parenchymalia. 

 On the other hand, in the Cauloj^hacidae — and, I may add, in 

 the E-OssellidiE — the corresponding spicules [I.e., the autodermalia) 

 apparently represent a more highly specialized category of spicules 

 which are joined to the parenchymalia only through the inter- 



■" Tliis condition of tlie dernialia is shared in a way also liy the I.eucopsacida?, in 

 ■which ]io\vever the denualia are pentactiiis or are at any rate always wanting in distally 

 directed rays. 



