96 Moll 
MOLLUSCOIDEA. 
Terebratula sphenoidea^ sp. n. [Philippi, 1844, foss. ?], recent specimen 
dredged on the Atlantic Coast of Spain ; A. Milne Edwards, C. E. xciii. 
p. 934. 
Waldheimia, Argiope and Bhynchonella. Median septum not constant 
in all species. Jeffreys, P. Z. S. 1881, pp. 948 & 949. 
TUNICATA. 
The late F. M. Balfour in his “ Treatise on Comparative Embry- 
vol. ii. (London: 1881), places the Tunicata under the name of 
“ Urochorda** between the Cephalochorda {Branchio stoma or Amphioxus), 
and the Elasmobranchia (sharks and rays), and subdivides them as 
follows : — 
I. Caducichordata. 
(a) Simplicia : Soliiaria (Ascidia), 
Socialia {Clavellina). 
{b) Composita : Sedentaria (JBotryllus). 
Natantia (^Pyrosomd).\ 
(c) Conserta : Salpidce. 
Doliolum. 
II. Perenniciiordata (Appendicularia). 
He describes the chief features of generation and development in these 
animals in his usual concise and clear manner, chiefly from the observa- 
tions of Kowalewsky, Huxley, and Krohn, with several woodcuts. 
E. Perrier, in “ Les colonies animales’* (Paris; 1881, 798 pp.), 
discusses the Tunicata in pp. 378-401 (more particularly Pyrosoma)^ 
pp. 378 & 388, the Salpce, pp. 389-391, and the compound Ascidians 
(pp. 391-396). He gives a general account of the morphology and 
development of these animals, and comes to the same general conclusion 
as Hackel, viz., that in the compound lower animals no absolute diffe- 
rence between organs and individuals is to be traced. The eggs in 
Pyrosoma belong, according to him, properly to the cyathozoid, but they 
are, as it were, handed over by it to the following really male individuals, 
and grow at their expense, somewhat like parasites ; in Salpa and some 
Ascidians also, the egg is contemporary with the individual which bears it, 
and rather its younger brother than its child. The tailed larva is, 
according to him, typical for the Tunicata, the exceptions are abbrevia- 
tions of development. With regard to general form, the fixed colonies 
(e.g., Botryllus) more resemble a Eadiate animal, and their individuals 
are rather more independent ; swimming colonies, on the contrary, as 
Pyrosoma (and the Siphonophora) exhibit a higher degree of partition 
of work, and the whole more resembles the complex organism of a 
higher animal. 
The literature of the Tunicata for 1880 is recorded by H. Fol in Zool. 
JB. Neap. ii. pt. 3, pp. 1-3. 
Firth of Forth, Tunicata enumerated by Herdman. P. Phys. Soc. 
Edinb. vi. 
