62 WALTER GARSTANG, M.A. 



Clavellina, Alder. Cat. Moll, of Northumberland and Durham. 

 Trans. Tyneside Nat. Field Club, 1848, p. 108. 



Clavelina, Forbes and Hanley, Hist. Brit. Moll., i, 1853, p. 26. 



Clavellina, Adams. Genera of Recent Mollusca, London, 1858, 

 vol. ii, p. 595. In part. 



Clavelina, Giard. Recherches sur les Synascidies, Arch. Zool. Exp., 

 i, 1872, p. 613. 



— Herdman. Prelim. Report on Tunicata of " Challenger," 



Proc. Roy. Soc. Edin., x, 1880, p. 717. In part. 



— Herdman. Rep. on Tunicata, " Challenger " Reports. 



vol. vi, p. xvii, p. 245. In part. 



— R. von Drasche. Die Synascidien der Bucht von Rovigno, 



Wien, 1883, p. 8. 



— Carus. Prodromus Faun., Mediterr., Stuttgart, 1890, 



vol. ii, pt. ii, p. 476. 



— Herdman. On the Genus Ecteinascidia and its Relations, 



with Descriptions of two new Species, and a Classifica- 

 tion of the Family ClavelinidEe, Trans. Biol. Soc. 

 Liverpool, vol. v, 1890, pp. 160, 161. 



Body oblong, more or less clavate, not provided with a post- 

 abdominal peduncle. 



Stolons distinct, delicate and branched. 



Professor Herdman has quite recently* subdivided this genus as 

 it was defined in his " Challenger " Report. The difference recog- 

 nised by Savigny between the types borealis and lepadiformis, in 

 regard to the presence or absence of a well-developed post-abdominal 

 peduncle of test-substance, is raised by him into a criterion of genei'ic 

 value (Podoclavella), while the rudimentary "common test" enclosing 

 the stolons of the " Challenger " species constitutes the salient 

 character of his new genus Stereoclavella. These changes have been 

 rendered desirable by an increase in the number of species and the 

 apparent f distinctness of the three types. As the table in Pro- 

 fessor Herdman's paper shows, the restricted genus now includes the 

 species lepadiformis (O. F. Muller), rissoana (M. Edwards ; variety 

 only?), pumilio (M. Edw.), producta (M. Edw.), Savigniana (M. Edw.), 

 and nana (Lahille). 



* On the Genus Ecteinascidia, &c, loc. cit. 



t One of the individuals in Milne-Edwards' figure of Clavelina producta 

 (1. c, pi. ii, fig. 3) exhibits a post-abdominal peduncle of some extent. 



