ANATOMY-DEVELOPMENT. 
Tun. 
o 
mantle appears to perform the respiratory and digestive functions ! Only 
a single specimen of this remarkable form is known, and it is difficult to 
believe that it is not an individual abnormality. Sluiter finds transition 
forms between the closely-allied genera Styela and Polycaiya , and is un¬ 
able to recognize any good distinction between them. 
Herdman (11) points out the remarkable development which the 
blood-vessels of the test assume in some groups of Simple and Compound 
Ascidians, and suggests that they may possibly act as an accessory respi¬ 
ratory system. He discusses also (10) the probable steps by w r hich such 
a complicated system was evolved from the simple blood-vessels of the 
stolon of the ancestral Claveliniclce. 
A detailed account of the minute anatomy of a form of Anchinia , 
without reproductive organs, from the Bay of Naples, is given by Wag¬ 
ner (30). 
Lacaze-Duthiers & Delage (17) describe the structure of Cynthia 
morus , which they take as a type of the French Cynthiidce. 
Herdman (12) points out that the minute scale-like structures lining 
the branchial siphon, described by Lacaze-Duthiers, were figured, in the 
case of Cynthia arenosa, in 1882, in the ‘ Challenger’ Report. 
Wagner (29, p. 124) gives a detailed account of the organization of 
Molgula grcenlandica , and especially of its circulatory system. He also 
describes more briefly some other species of Simple Ascidians. He draws 
attention to the prevalence of short-bodied species in the White Sea, and 
regards them as simpler and more primitive than long-bodied forms. He 
considers Chelyosoma as a very primitive form, on account of its flattened 
shape. 
Herdman (14) points out that calcareous spicules, apparently capable 
of being preserved in a fossil condition, exist in several distinct groups of 
Tunicata, and should be looked for by palaeontologists. [Such spicules, 
apparently belonging to the Didemnidce , have since been discovered b} r 
Mr. Kendall, at St. Erth, Cornwall.] 
Roule (20) gives a detailed account of the anatomy and histology of 
Ciona intestinalis, as a type of the Phallusiadce (Ascidiidce), and describes 
more briefly the other species of the family occurring on the shores of 
Provence. He divides the old genus Phallusia (Ascidia ) into three new 
generic groups— Ascidiella, Ascidia , and Phallusia. He alsa (21) re¬ 
describes, wdth anatomical details, many of the old and imperfectly known 
species of Savigny and others. 
Physiology. 
Lahille (18) describes the results of his observations and experiments 
upon the beating of the heart in various Tunicata. He notes consider¬ 
able irregularity and modification under abnormal circumstances, and 
after treatment with carbonic acid or removal of the nerve ganglion. 
Development. 
Sabatier (22) discusses the structure of the ovary of Ascidians and 
the formation of the ova. He finds that the follicle-cells are formed 
