116 ALT. 1. — I. IJIMA : HEXACTINELLIDA, lit. 



first t 111 the last exactly correspond in scope, each to each, to 

 two of the three Hexastero}fhora tribes in my system which I 

 have provisionally designated witli the fiist three letters of the 

 alphabet (p. 25, /. c), namely, to the tribes C and A respectively. 

 On the other hand, Schrammen's luermia differs from the tribe 

 B of my system in that all the lychniscophorous forms (which, 

 as above mentioned, are made by him into the Lychniscosa) are 

 excluded from it ; whereas I place them under the tribe B, 

 together with, but as representing a family or families distinct 

 from, the Dactylocalycidae {Dactylocalyx, Jfyliusia, etc.). This 

 is the point in which I stand in disagreement with Schuammen, 

 — a disagreement which I am strongly inclined to regard as due 

 to an over-estimation, on his part, of the lychnisc as a systematic 

 character. 



The diagnoses of the Hexactinosa and the I^ychniscosa, as 

 given by Schrammen and cited above, appear to me as wholly 

 inadequate to characterize the grou])S. The Hexactinosa is stated 

 to have the supporting framework composed of Jiexactlns. This 

 may be said to hold good for the dictyonine forms of that grou]) 

 but not for all : a mere reference to the parenchymalia in the 

 Euplectellaria is sufficient. Be that as it may, the lychnisc, 

 which should characterize the Lychniscosa as opposed to the 

 Hexactinosa, is, fundamentally, likewise a hexactin or a part of 

 a hexactin ; it is clearly a secondary structure or complication 

 which has for its basis hexactins, such as compose an ordinary 

 dictyonal skeleton (see Marspiall u. Mayer, Mittli. kgl. Zool. 

 Mus. Dresden, 1877, p. 267 ; F. E. Schulze, Hexactinelliden 

 des Kothen Meeres, 1900). Therefore, the supporting framework 

 of the Lychniscosa is, in my way of thinking, as really composed 

 of hexactins as that of certain Hexactinosa. The Ivchnisc as a 



