ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 587 



Poison of the Edible Mussel.* — Dr. G. Baumert reports that on 

 examination the poison of the mussel was found by Herr E. Salkowski 

 in a cold alcoholic extract of the substance of tbe mollusc ; watery 

 extracts were also poisonous ; these results were obtained by physio- 

 logical experiments. Tbe chemical investigation of Herr Brieger 

 showed that there was a non-poisonous base, the specific mussel-poison, 

 an extremely poisonous substance which produced a copious flow of 

 saliva and diarrhoea, but was not mortal, and a decomposition -product 

 of poisonous properties. The mussel-poison appears to belong to the 

 group of ptomaines, and is therefore a decomposition-product of the 

 flesh of the mussel. Dr. Schneidemiihl is of opinion that the liver is 

 the seat of the poison, therein agreeing with Salkowski. 



Molluscoida. 

 a. Tunicata. 

 Phylogeny of the Tunicata.f — Prof. W. A. Herdman, referring 

 to the views expressed by Dr. Uljanin in his monograph on Dollolum, 

 agrees to the suggestion that the Appendiculariidse gave rise to other 

 Ascidians, but doubts the origin of the Salpidae and the Doliolidfe 

 from groups of the simple Ascidians ; he thinks it unlikely that the 

 Thaliaceae were ever fixed simple Ascidians. He would regard the 

 simple and compound Ascidians as being derived from a common 

 ancestor resembling the simpler forms of the two groups, in preference 

 to supposing that the compound were derived from the simple ; many 

 of the latter show far more differentiation and specialization of certain 

 important organs (e.g. the branchial sac in the Molgulidaa) than is 

 found in any of the compound forms. He protests against Uljanin's 

 view, that the social are derived from the compound and have no 

 close connection with the simple Ascidians ; for there is a very close 

 relationship between the Clavelinidaa and the Ascidiidae, and the 

 " social " group seems to be distinctly intermediate between the least 

 modified form of the two other groups. Pyrosoma, it is agreed, is a 

 modified compound Ascidian, but Prof. Herdman thinks it is derived 

 from the Didenmidas and not from Distaplla ; this last is not as ex- 

 traordinary a form as is generally supposed. The compound Ascidians 

 appear to have had a polyphyletic origin. 



0. Polyzoa. 

 Researches on Blastogenesis.J — M. L. Joliet, in discussing the 

 gemmation of marine ectoproctous Bryozoa, deals particularly with 

 the criticisms on his previous work which have been made by Prof. 

 Haddon and Dr. Vigelius. He comes to the conclusion that there is 

 only a single homogeneous tissue — the apical endocyst — at the vege- 

 tative end of a stolon or cell of a gymnoloematous form ; this is 

 neither ectodermal nor endodermal, but is an indifferent tissue. In 

 some species no other tissue than the parietal endocyst, from which 

 the polypide and the sexual are formed, is to be found; in most, 



* Zeitschr. f. Naturwiss., lix. (1886) pp. 60-2 v 



t Nature, xxxiii. (1886) pp. 546-7. 



% Arch. Zool. Exper. et Gen., iv. (1886) pp. 37-72 (2 pis.)- 



