of Edinburgh, Session 1879 - 80 . 717 
The first Social Ascidians known to science were two species of 
Clavelina , viz., C. borealis and C. lepadiformis. 
The first of these, Clavelina borealis, was described under the 
name Ascidia clavata by Pallas* in 1774, and was referred to by 
Bruguieref in 1789. It was afterwards, in 1815, described at 
greater length under the same name by Cuvier, J who united it with 
Ascidia (now Ciona) intestinalis to form his fourth tribe of the 
genus Ascidia. 
The second species, Clavelina lepadiformis , was observed by 
Muller § and described by him in 1780 under the name of Ascidia 
lepadiformis ; Bruguiere|| (1789) mentions this species also. 
In 1816 SavignyH founded the genus Clavelina for the reception 
of these two species, which he separated from Phallusia (Ascidia) 
on account of their being pedunculated. He still retained them, 
however, in the Simple Ascidians. In his third memoir (p. 109) 
he gives an account of Clavelina borealis , and states (p. 110) that 
“Les veritables rapports des Clavelines sont avec les Phallusies.” 
In his systematic table (p. 171) he places Clavelina as the last 
genus of the Simple Ascidians next to Phallusia, and immediately 
following the Phallusice Cionce (C. intestinalis). 
In the same year (1816) Lamarck** places these two species, C. 
clavata and C. lepadiformis, in the genus Ascidia. 
It is evident, then, that those of the older naturalists to whom 
any of the ClaveliniDjE were known included them unhesitatingly 
in the Simple Ascidians. It must be remembered, however, that 
although Gaertner was acquainted with Botryllus and Distomus in 
1774, and Eenieri (1793) was to a certain extent aware of the true 
nature of some of these forms, yet the Compound Ascidians were 
hardly recognised as such till after the appearance of Savigny’s well- 
known memoirs. By Cuvier, Savigny, and Lamarck, however, to all 
of whom the Compound Ascidians were well known, Clavelina was 
considered a Simple Ascidian closely allied to Ciona intestinalis. 
* Spicilegia Zoologia, fasc. 10, pi. i. fig 16. 
t Encyclopedic methodique, pi. lxiii. fig. 11. 
X Mem. du mus. d’hist. nat. , t. ii. pi. ii. figs. 9, 10. 
§ Zoologia Danica, Pt. ii. p. 119., tab. lxxix. fig. 5. 
|| Loc. cit., pi. lxiii. fig. 10. 
IF Memoires sur les animaux sans vertebres, Pt. ii. , fasc. 1, p. 87. 
** Histoire naturelle des animaux sans vertebres, t. iii. p. 126. 
