334 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



In addition to the genera represented in the collection. Donatio, 

 and Tuberella, the family includes: Tethyorrhaphis Lendenfeld 

 (1888), Xenospongia Gray (1858), Trachya Carter (1870), Het- 

 eroxya Topsent (1898), and Halicometes Topsent (1898). (See 

 Topsent 1920^, p. 33.) 



For forms with streptasters an appendix to the family may be 

 created. Scolopes Sollas (1888), with amphiasters instead of 

 euasters, would be classed here. Topsent (1898, p. 108) pointed out 

 that it was nearly related to the Donatiidae. 



Topsent (1898) assigns Xenospongia, somewhat doubtfully to be 

 sure, to the Spirastrellidae. Dendy (1905) after original study of 

 a good specimen refers it to the Donatiidae. 



Dendy (1916, p. 259) is inclined to think that if '"epipolasid"' 

 forms, such as certain species which he refers to Aurora (see Aurora 

 under Stellettidae), are admitted into the Stellettidae, then possibly 

 the whole family of Donatiidae should be merged in the Stellettidae. 

 He nevertheless retains the family, although he would limit it, pos- 

 sibly excluding the oxeate forms : Trachya and Heteroxya. 



Thiele's suggestion (1903, p. 965) that the name Donatia should be 

 used for Tethya Authors and Tethy a for Craniella Authors has been 

 followed by many, Lendenfeld (1903) adopting Tethya in the latter 

 sense and Baer (1906) introducing the name Donatiidae for Tethy- 

 idae Authors. Dendy (1916 p. 260) reviews the matter and thinks 

 the wisest course would be to abandon the generic name of Tethya 

 altogether, since Lamarck included very diverse sponges under this 

 name without indicating any one as the type species. Topsent has 

 recently (19205) made out a good case in equity for the practice that 

 was common before 1903 — namely the use of Tethya for hadro- 

 merine sponges such as Alcyonium aurantium Pallas (= A. lyn- 

 curium Linnaeus) — and it seems to me regrettable that any 

 change was ever made in this custom. Still Tethya in such a sense 

 appears to have no valid claim in strict law while Donatia has. 



Topsent, who (19205) has recently gone through the older litera- 

 ture on this matter, is convinced that Tethya can not be used for a 

 sigmatophorous sponge, since T. (Alcyonium) cranium O. F. Miiller. 

 included by Lamarck under Tethya, is not such a sponge, Johnston 

 (1842, p. 83) being in error when he picked this name for his own 

 sponge which plainly is a sigmatophorous form. For this (sigma- 

 tophorous) type Topsent advocates Craniella Schmidt (1870), thus 

 upholding the practice of Sollas as against that of Gray, Carter (see 

 Sollas, 1888, p. cxxii), Thiele, and Lendenfeld. Sollas ? practice 

 in this matter, adhered to by Topsent (1904, 19206). Dendy (1905), 

 and Kirkpatrick (1908) should, I think, be followed. 



