216 THE ROYAL SOCIETY OF CANADA 



been of doubtful systematic position until recently, when we (Hunts- 

 man, 1922) showed it to be identical with the Clavelina chrystallina of 

 Moller (1842), which was obtained at Greenland. Cystingia is, 

 therefore, the second named genus in this family. 



In 1834 Quoy et Gaimard described the species Ascidia tumulus, 

 obtained at Australia. It was described in detail by Pizon in 1898. 

 Hartmeyer (1914, p. 3) has called attention to the fact that Gervais 

 in 1840 instituted the genus Syphonotethis for this species. 



In 1848 Forbes formed the genus Molgula for the species M. 

 oculata and M. tuhulosa. This genus was the first genus of the family 

 to be generally adopted and recognized by systematists, and, when 

 the family was separated by Lacaze-Duthiers in 1877, it was con- 

 sidered the oldest genus, and the family was accordingly called the 

 Molgulidae, by which name it has gone until quite recently. 



Since the middle of the last century there has been a steadily 

 increasing number of species and genera added to this family. 



The Classification 



The current classification of this family is particularly unsatis- 

 factory as it lacks any sub-division of the heterogeneous genus Caesira 

 or Molgula. The history of the family has largely been a continued 

 separation of small genera from the old, comprehensive genus Molgula. 

 Many of the new groups proposed have not met with general accep- 

 tance, so that Molgula has become to an increasing extent an unsatis- 

 factory assemblage of diverse species. 



Giard in 1872 proposed the genera Gymnocystis and Lithonephrya, 

 neither of which have been recently recognized. In founding the 

 family in 1877 Lacaze-Duthiers instituted the genera Anurella and 

 Ctenicella, of which the latter alone has gained any currency. Pizon 

 in 1898 and 1899 introduced the genera Gamaster, Astropera, Stoma- 

 tropa, and Meristocarpus, of which only the first has been accepted. 

 In more recent times we have Seeliger's (1907) Molgulidiuni and 

 Eugyrioides, and Hartmeyer 's (1914) Fareugyrioides and Molgulina. 

 Of these four the second and third appear sufficiently well character- 

 ized to be valid. No matter what classification proves best there is 

 at our disposal a considerable number of generic names for use in 

 accordance with the International Rules of Nomenclature. In the 

 classification that we propose, these will be used wherever available, 

 but with frequent alteration of diagnosis and scope. 



The importance of any group of characters for classificatory 

 purposes varies in inverse ration with their variability and the extent 



