4 Tun. 
TUNIOATA. 
and the two most important conclusions arrived at in regard to its further 
history are : (i) Pyrosomti, although now a pelagic free-swimming organism, 
was derived from the fixed Compound Ascidians, to which it is related 
through Coslocormus huxleyi ; (n) the Ascidte Composite are a poly- 
phyletic group, being derived from the ancestral Simple Ascidians at 
three distinct points, and consequently the Compound Ascidians form 
three groups : (1) the Polystyelidce , (2) the Botryllidce, and (3) the 
remaining families, which are more nearly related to particular sets of 
Simple Ascidians than they are to one another. 
SYSTEMATIC. 
LARVAOEA . 
Herdman (4) gives a definition and a general account of the structure 
and history of the Appendiculariidce , with diagnoses of the four genera — 
Appendicular ia : Oilcopleura, Fritillaria , and Kowalevskia — and a record of 
the localities at which Appendicularians were found during the ‘ Chal- 
lenger’ expedition. No new species are described. 
Stegosoma } n. g., Chun (2). 
THALIACEA. 
A definition and a general account of the history, structure, and 
development of this order, and of the two suborders Cyclomyaria and 
Hcmimyaria , are given in the ‘Challenger’ Report. 
CYCLOMYARIA. 
Fam. Doliolidas. 
Doliolum tritonis , Herdman [formerly described as D. denticulatum , in 
Tr. R. Soc. Edinb. (5) xxxii, p. 93], (4) p. 47. 
• Doliolum affine, n. sp., id. ibid. 
Doliolum challenged , n. sp., id. t. c. p. 48. 
Doliolum krohni , n. sp., id. t. c. p. 49. 
HEMIMYARIA. 
Fam. Salpim:. 
The specific nomenclature of Salpa is discussed [Herdman (3)], aud it 
is suggested that the names of both the solitary and the aggregated forms 
be given — e. g., Salpa runcinata-fusifonnis , Chamisso-Cuvier. . 
Salpa sp. (?), n. sp., Herdman, (4) p. 62. 
Salpa musculosa , n. sp , id. t. c. p. 64. 
Salpa echinata , n. sp., id. t. c. p. 66. 
Salpa mollis , n. sp., id. t. c. p. 68. 
S(dpa nitida , n. sp., id. t. c. p. 81. 
Salpa quadrata , n. sp., id. t. c. p. 84. 
