470 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Family VETULINIDAE. 



Vettdinidae Lendenfeld, 1903, p. 149. 

 Anomocladidae Soi.i.as, 1S88, p. 354. 



Family DESMANTHIDAE. 



Desmamrthidae Topsent, 1893b, pp. xxxvi-xxxvn ; 1894b, p. 311; 189S&, 

 p. 231. — Kirkpatrick, 1902b, p 176. — Lexdexfeld, 1903, p. 144. 



Lendenfeld (1903, p. 144) restricts the family to forms with 

 tetracrepid desmas. But Kirkpatrick (19025) uses it in the wider 

 sense of Topsent, 18985, to include those with monocrepid desmas as 

 well. While this runs counter to the principle (Zittel\s) followed in 

 Sollas' system, according to which genera with tetracrepid desmas 

 (Theonellidae) are separated from those with monocrepid desmas 

 (Corallistidae,now Coscinospongiidae), it is in strict logic admissible 

 since it sometimes happens that along with monocrepid desmas some 

 tetracrepid ones may occur in the same individual even (O. Schmidt, 

 1879, p. 24; Sollas", 1888, p. 342; Topsent, 1904, p. 60). In the 

 known instances of this combined occurrence of the two types, the 

 aberrant (tetracrepid) desma includes a crepis, three rays of which 

 are short and one long, and which is regarded as a degenerate 

 tetraxon spicule. The family (Coscinospongiidae) in which these 

 instances occur is defined as having a monocrepid desma. The 

 occasional occurrence of imperfect tetracrepid desmas may be re- 

 garded as reversional. The case of the Desmanthidae is somewhat 

 different, since here a form, Monanthus, with monocrepid desmas 

 is combined with another, Desmanthus^ having tetracrepid desmas 

 (modified triaenes ) . 



In addition to the single species given by Lendenfeld (1903) the 

 list now includes Desmanthus topsenti (Hentschel, 1912. p. 307) and, 

 using the family in the wide sense, Monanthus (new genus) plu- 

 mosus (Kirkpatrick, 19026). 



Thiele (18996) has suggested, but without sufficient reason, that 

 Desmanthus is really a monaxonid sponge, and Kirkpatrick (19025) 

 touches on the same question with respect to Monanthus. 



Thiele's suggestion (18995) that MaiwcrepMium (new genus) 

 v< rmiculatum, (Topsent 18986, p. 229), originally assigned to this 

 family by Topsent, is a monaxonid sponge, allied to Bubaris, has 

 been accepted by Topsent (1904, p. 148). In their external form and 

 in the way they interlock, the megascleres of Monocrepiditttn pre- 

 sent some analogies to the simple rodlike desmas of Costifer vasi- 

 formis of this report. 



