54 SUMMARY OF CURRENT RESEARCHES RELATING TO 



gills, the infundibula of the latter being alone simpler in the Cyn- 

 thiidse ; the intestine of Cynthia describes a wide curve, that of 

 Molgula is looped, and the heart is longer and more anteriorly placed ; 

 notwithstanding these and other slight differences we can easily pass 

 from the Molgulid to CyntJiia morus ; the more aberrant Cynthiidae 

 of course present greater difficulties. 



j8. Polyzoa. 



Morphology of Polyzoa.*— Dr. A. A. Ostrooumoff notes the 

 most important discoveries in a forthcoming work on the Polyzoa of 

 the bay of Sebastopol. 



The calcareous skeleton is formed in the ectoderm which exists 

 throughout life, either as a subskeletal layer (Memhranipora), or as 

 two layers between which is the skeleton (Lepralia). The body- 

 cavity contains " mesenchymatous " (Hertwig) elements, and is not 

 lined by an endothelial layer. The internal sac of the larva forms 

 in the Chilostomata the basal face, in the Vesicularias the stolo 

 prolifer ; from these regions alone are formed by budding the new 

 members of the colony, with the exception of certain pallial avicu- 

 larise. What is termed the polypide is formed from the ectodermal 

 rudiments, plus the brown body. The paper concludes with some 

 observations upon the metamorphosis of the Bryozoa, illustrated by a 

 diagram of a " Probryozoon." 



New or little known Polyzoa. f — Dr. P. H. MacGillivray, in two 

 papers, describes two new genera and several new species of Polyzoa. 



Maplestonia (n. gen.) consists of a series of single or geminate 

 cells, which are membranous in front and imperforate behind ; there are 

 no avicularise nor vibraculse ; it belongs to the Celleporidse. M. cirrata 

 has the cells in a linear series ; the posterior surface is transversely 

 striated. M. simplex branches dichotomously, at the angle of a cell ; 

 posterior surface smooth. 



Favosipora (n. gen.) consists of an adherent zoarium, raised at 

 intervals into rounded ridges. It belongs to the Biscoporellidse. 

 F. rugosa is allied to Densipora corrugata. 



The new species belong to the following genera : — Cellaria, Tuhu- 

 lipora (6), Diastopora (3), Catenicella, Cauda, Tuhucellaria, Beania, 

 UrceoUpora, Cahasea, Memhranipora (2), Microporella (2), ScMzoporella, 

 Lehyihopora, and Cellepora (6). 



y- Brachiopoda. 



Recent Brachiopoda. | — In the first part of an exhaustive mono- 

 graph on recent Brachiopoda, by the late Dr. T. Davidson, the author 

 reviews the labours of his predecessors with regard to the shell, the 

 anatomy of the adult, and the embryology. As regards the per- 

 plexing question of affinities, he remarks : — " Now, although I do not 

 admit the Brachiopoda to be worms, they, as well as the MoUusca and 



* Zool. Anzeig., viii. (1885) pp. 577-9. 



+ Trans, and Proc. Roy. Soc. Victoria, xxi. (18S5) pp. 92-9, 106-19 (8 pis.). 



X Trans. Linn. Soc. Lond.— Zool., iv. (1886), not yet published. 



