REPORT ON TIIE TUNICATA OP PLYMOUTH. 61 



without papillae or internal longitudinal bars ; dorsal lamina con- 

 sisting of a series of languettes flattened antero-posteriorly and 

 continuous with the horizontal membranes ; stigmata straight. 



Tentacles, simple, filiform. 



Genitalia in the loop of the intestine ; oviduct and vas deferens 

 present. 



Reproduction by gemmation as well as from ova. 



The family, as thus defined, includes the general Clavelina 

 (Savigny), Podoclavella (Herdman), Stereoclavella (Herdman), and 

 a new genus, Pijcnoclavella, described below. 



I believe there is abundant reason for dividing the family 

 Clavelinidae, as regarded by Herdman, into several groups ; 

 Perophora, indeed, was excluded by Giard in 1872, and by von 

 Drasche in 1883, while still more recently Lahille (1890) has empha- 

 sised the differences between Clavelina and Perophora by placing 

 the former genus in the Distomidse and the latter in the Ascidiidae. 

 Von Drasche's family Clavelinidas includes Diazona, but although a 

 near relationship between Clavelina and Diazona is generally 

 admitted, it must be remembered that the new forms discovered in 

 recent years have rather emphasised than reduced the gap between 

 the two genera ; I have therefore excluded Diazona from the 

 Clavelinidae altogether. As above defined, this family includes a 

 number of forms about whose close mutual affinity there can be no 

 doubt. 



1. Clavelina, Savigny. 



Ascidia, 0. F. Mutter Zoologia Daniea, vol. ii, 1788. In part. 



— Bruguiere. Hist. Nat. des Vers, Encycl. Methodique, Paris, 



1792, p. 141. In part. 



— Turton. Linne's General System of Nature, London, 1802, 



vol. iv, p. 92. In part. 



Clavelina, Savigny. Memoires sur les Animaux sans Vertebres, 

 Paris. 1816, He Partie, pp. 87 and 109. In part. 



— Savigny. Tableau system ati que des Ascidies, p. 171. In 



part. 



— Fleming. Molluscous Animals, Edinburgh, 1837, p. 202. 



In part. 



— M. Edwards. Observations sur les Ascidies des Cotes de 



la Manche Mem. de l'Acad. des Sci., Paris, xviii, 181-2, 

 p. 50. In part. 



