2 Tun. 
TUNICATA. 
11. Salensky, W. Zur Entwicklungsgeschichte der Pyrosoma. Biol. 
Centralbl. x, No. 8, Juno 1, 1800, pp. 225-233. 
. 12. . Beitriige zur Embryonalentwicklung der Pyrosomen. Zool. 
Jahrb. iv (Abth. f. Auat. and Ontog.), lit. 3, pp. 424-477, pis. 
xxvi-xxviii. 
13. Sluiter, C. Ph. Die Evertebraten aus der Sammlung des Konig- 
lichen naturwissenschaftlichen Yereins in Niederlandisch Indien in 
Batavia. Nat. Tijdschr. Nederl. Ind. 1, 1890, pp. 329-348, 2 pis. 
14. Swainson, G. Appendicularia with its “ Haus.” Internat. J. Micr. 
& Nat. Sci. iv, pp. 10-19. 
15. Wagner, N. C. Uber das Nervensystem der Tunicaten. Biol. 
Centralbl. x, pp. 425 & 426. 
ANATOMY. 
In his work on the French Tunicata (8), Lahille gives a description 
of the anatomy and histology of Pegea ( Salpa ) con/cederata , of Pyrosoma , 
and of some of the Compound Ascidians. He gives a good account of 
the structure of the rudimentary gill of Salpa , and compares it with the 
branchial sac of Ascidians, showing that it is formed of a single oblique 
row of partially-developed stigmata. He introduces convenient formulae 
for giving in brief the branchial characters of the species of Doliolum. 
He regards the circular muscle-bands of Salpa and Doliolum as being 
homologous with the sphincter muscles of a Compound Ascidian, such as 
Aplidium. He finds that in the Didemnidce the two primitive lateral 
atrial involutions do not meet dorsally, but remain closed at their inner 
ends, and are replaced functionally by a median dorsal cloacal invagination. 
Sluiter (13) and Herdman (7) describe the details of structure of 
some new species of Simple Ascidians. 
EMBRYOLOGY. 
Davidoff, in this second part (4) of his elaborate memoir on the deve- 
lopment of Distaplia magnilarva , gives a very detailed account of the 
segmentation and gastrujation, the origin and development of the meso- 
derm, the formation of the endoderm, and of the notochord, and the 
development of the nervous system in the embryo of this typical Com- 
pound Ascidian. 
Lahille (8) gives good figures of the tailed larvae of many of the 
genera of Compound Ascidians. 
Morgan (10) now gives a fuller account of his investigations on the 
origin of the test-cells of the Ascidian embryo (see last year’s Record, 
Tun. 3). In his results he agrees fully with Yan Beneden and Julin, and 
is diametrically opposed to Davidoff. He derives the test-cells entirely 
