cxlvi GENERAL SUMMARY OF SCIENTIFIC AND 



The embryology of the Ascidians has been studied by Pro- 

 fessor Giard. He finds a curious assemblage of parasites on 

 the compound Ascidians of the coast of France, and some 

 interesting cases of mimicry. A shell-fish (Lamellaria) and 

 a naked mollusk ( Go?iiodoris), a flat worm (Planaria), as well 

 as a sponge, imitate these Ascidians so completely that the il- 

 lusion is, he says, perfect. He also finds that certain com- 

 pound Ascidians mimic simple ones. 



Drs. Metschnikoff and Nitsche have been publishing on the 

 development of the Polyzoa; while Dr. Smitt, of Stockholm, 

 has completed his account of the deep-sea forms dredged by 

 Count Pou rt ales in the Floridan Channel. He finds that 

 some species are cosmopolitan in range, while others have 

 survived from the cretaceous period. 



The development of the Brachiopoda has been studied by 

 Kowalevsky, and, independently of Professor Morse, he has 

 arrived at quite similar results, both in matters of detail and 

 general conclusions. He thinks, with Morse, that these ani- 

 mals, heretofore classified with the Mollusca, are really allied 

 to the Chsetopod worms. 



The singular fact is brought out in Claparede's remark- 

 able posthumous work on worms that in several families 

 (JSerpulidce, Ammocharidce, Aricidce, and Chmtopteridaz) the 

 intestine is inclosed in a vascular sac, which acts as a dorsal 

 vessel, there being no true heart. This reminds one of the 

 Mollusca in which the intestine normally passes through the 

 heart. 



The higher worms of the coast of New England have been 

 enumerated, and many new and interesting forms described 

 and figured by Professor Verrill, in his report on the in- 

 vertebrates, published as an appendix to Professor Baird's 

 United States Fish Commission Report. 



A singular fact in the structure of some of the higher 

 worms (annelids) has been observed by Professor Moebius, 

 who figures a species (Leipoceras uviferum) with external 

 ovaries. Another worm has been said by Sars to carry 

 its eggs in pouches resembling a swallow's nest along the 

 hinder segments of the body. Other anomalous modes of 

 carrying the eggs are noticed in the same paper. 



Dr. Willemoes - Suhm states his belief that the asexual 

 Guinea-worm (Filaria medinensis) has possibly males of mi- 



