6 Tan. 
VI. TUNICATA. 
become pelagic and progenetic. The fixing point (stolon) is praeoral on 
the anterior lobe, and in Ciona the longitudinal muscles converge to it. 
The pericardium arises from the endoderm of the branchial sac. 
In his II “ Studies ” (34) he has worked at the later development of the 
nervous system in Ciona , and finds it is different from what is described 
by van Beneden and Julin. He also deals with the closure of the neuro- 
porus and the origin of the sense organs in Ascidia mentula , and the 
origin of the neuro-hypophysial system in Ciona and in Clavelina. 
In the III series, Willey deals with the position of the mouth in the 
larvae of the Ascidians and Amphioxus , and its relations to the neuro- 
porus. He considers that the hypophysis of the Ascidians is repre- 
sented by the olfactory pit of Amphioxus , and that the primitive mouth 
was dorsal. 
Garstang (7) corrects an error of Salensky in regard to the develop- 
ment of the stigmata in Pyrosoma , which never have their long axes 
parallel to the endostyle either in adult or embryo. 
Julin (14) gives an account of ovogenesis, spermatogenesis, and fer- 
tilization in Styelopsis grossularia. He considers the polar bodies to be 
aborted ova. 
D. — PHYSIOLOGY. 
From a study of the beating of the heart in Perophora , Ritter (22) 
comes to the conclusion that the reversal is due to regurgitation caused 
by engorgement of the capillaries. 
The nutrition of the Salpa embryo, and a number of other more 
or less physiological matters in connection with Salpa } are discussed by 
Brooks (5). 
III.— GEOGRAPHICAL DISTRIBUTION. 
Meissner (16) describes specimens of Ascidiella virginea from the 
Biological Station at Heligoland, with Crenella marmorata imbedded in 
the test. 
Heiden (8) records 24 species of Compound Ascidians from the Island 
of Minorca, and of these 13 are new species. 
Borgert (1) discusses the synonymy of Doliolum denticulatum , and 
describes a new closely-related species (D. nationalist obtained in the 
Atlantic during the “ Plankton” Expedition. 
Mcebius (19) records Cynthia rustica and Oikopleura Jlahellum from 
the oyster banks off the German Coast. The former is, however, more 
probably Styelopsis grossularia , which is commonly found on oyster 
shells in British waters. 
Metcalf (18) records a new form of Odacnemus obtained from a depth 
of 1050 faths., off the east coast of Patagonia by the “ Albatross.” The 
genus was only previously known from the South Pacific. 
