EMBRYOLOGY. 
Tun. 5 
Caullery (2), in investigating the degeneration in colonies of 
Distaplia , finds that in D. magnilarva the colonies are unisexual. He 
supports, in the main, Salensky’s account of the process of degeneration 
by phagocytosis, but considers that the testa-cells are derived from the 
follicular epithelium. 
Calman gives a description of the general anatomy of Julinia 
australis , proposed as a new genus of the Distomidcc. 
Apstein, in his account of the Salpcc of the Plankton Expedition, gives 
a description of the structure of a few of the less known forms, including 
S. virgula , S. fusiformis var. echinala , and S. rostrata , and the new species. 
Borgert gives an account of the general structure and of the life- 
history of Doliolum in his Plaukton Expedition report. 
C.— EMBRYOLOGY. 
Samassa finds, in Ciona and Clavellina , just as Davidoff found in 
Distaplia , that the four dorsally placed blastomeres form the endoderm, 
and the four ventral the ectoderm. 
Willey in support of his view, that the anterior extremity of the 
Ascidian larva is a prneornl lobe, suggests that in Protochordates and 
Vertebrates it has become completely freed from the nervous system, so 
that in Vertebrates the nervous elements of the invertebrate praeoral 
lobe are completely wanting, while the mesoderm element has given rise 
to the pre-mandibular head cavities. 
Caullery (1) supports Kowalevsky’s view that in the Polyclinidcc the 
reproductive organs of the bud arise directly from those of the parent. 
He examined Circinalium coiicrescens and Polyclinum luteum , and found in 
the buds, in all cases, a continuous genital tube which could be traced 
to the genital epithelium of the parent. 
Pizon finds practically the same continuity in the Didemnidm and 
Diplosomidcc , and considers that the generalisation may be extended to 
all compound Ascidians. 
Caullery (3) finds that in the Diplosomidcc the epicardial tubes per- 
sist in the adult and play a leading part in the formation of the buds. 
They chiefly form the thoracic and abdominal buds which fuse to consti- 
tute the new individual. 
Castle has studied the early stages in the development of Ciona 
intestinalis , and he explains the fact that Seeliger’s statements conflict 
with those of Van Beueden and Julin by declaring that he has detected 
fundamental errors in the work of each of these authors, Seeliger having 
reversed the anterior and posterior ends in all his figures of early stages, 
and Vau Beneden and Julin having confused the dorsal and ventralsides. 
He also ditfers entirely from Samassa in regard to the cell-lineage. On 
correcting the orientation Castle finds that it is the four larger, not the 
four smaller cells, which give rise to the greater portion, perhaps all, of 
the ectoderm. He finds that the polar bodies form in what afterwards 
becomes the centre of the dorsal or endodermal half of the egg. 
