4 Tim. 
VI. TUNIC AT A. 
Seeliger discusses the structure of the tail of Appendicularia in 
relation to segmentation. 
Hunter has found in Molgula manhattensis and in Cynthia partita that 
the endostyle contains many sensory bipolar cells. They are situated 
amongst the fusiform ciliated cells on the lateral wall of the groove. He 
has also found nerve endings in some of the ciliated cells of the peri¬ 
pharyngeal bands and of the branchial sac. The sensory nature of the 
tentacles has been demonstrated, and that of the dorsal tubercle (stated 
previously by various authors) has been confirmed. Muscle endings have 
been found in the body musculature and sensory papillae in the ectoderm. 
Hartmeyer finds in two species (1 new) of the genus Dendrodoa from 
East Spitzbergen the presence of a more or less well-developed brood- 
pouch as a membranous sack given off from the peribranchial cavity, and 
containing tailed larvae. 
Pizon finds the colouration of Compound Ascidians due to very minute 
pigment granules which lie in vesicles and show a rapid movement. 
Perrier in his textbook has reached Amphioxus and the Tunicata, and 
gives an interesting account of the latter group, rather detailed in some 
sections, such as that on budding, and illustrated by many figures. 
Herdman, in the introduction to his Catalogue of Australian Tunicata, 
gives an account of the structure of a typical Ascidian ; and other 
anatomical descriptions are scattered through the work. The L. M. B. C. 
memoir on Ascidia by the same author contains a detailed account of the 
' anatomy and histology of that type. 
b. Physiology. 
Loeb, in connection with the comparative physiolog} 7 of the nervous 
system, has a chapter on the ganglion in Ciona , and its reflex actions. 
Metcalf has shown that the -so-called otocysts of Salpa are really 
glandular organs very possibly related to the neural gland of Ascidians. 
The two pairs of small eyes in the ganglion of Salpa which Delage and 
Herouard suggest may be otocysts are according to Metcalf, who described 
them, exactly similar in structure to the larger eye, and cannot be of an 
otocystic nature. 
Lohmann has given us a very complete account of the structure and 
functions of the cuticular “House” of the Appendicularians. It is formed 
by special ectoderm cells called “ oikoplasts ” and can be completed in 
3 or 4 hours, and then may be cast off and replaced by another a few 
hours later. He considers that the “house” serves several functions. It 
is a fishing apparatus or trap for straining the water and entangling 
microscopic food particles. It helps in locomotion by its hydrostatic 
effect; and it is also a protection to the animal, which may escape from 
enemies by throwing oft’ the house. 
Schultze finds that when an Ascidian is anaesthetised and the ganglion 
removed it becomes regenerated from the lining of the peribranchial 
cavity, a layer which like the ganglion is epiblastic in origin. 
Bancroft shows that the ampullae on the ectodermal vessels round the 
margins of the colony in Botryllidae in addition to acting as storage 
reservoirs for blood, organs for the secretion of test matrix, and for 
respiration, are also organs for blood propulsion. He found no trace of 
a reproductive function. The ampullae execute co-ordinated pulsations, 
the co-ordination being due to variations in the blood pressure. The 
ampullae can keep up the circulation for some time independently of the 
hearts of the zooids. 
