MiticeUaiicous. 443 



to Dr. Carpenter the number is variable, Prof. Verrill having counted 

 from four to six in some specimens. Those fcnestrje in this species 

 are more compHciited than in most chitons which I have examined. 

 1 have never been able to satisfy myself that there is a true oviduct ; 

 and it may be that the ova are dehiscent in tlie perivisceral cavity, 

 and may be expelled through the fenestra^ as they are through the 

 analogous " oviducts or segmental organs" of brachiopods. 



The fact that the ovarian openings are not simple apertures was 

 noticed by me in dissecting chitons in ISfJ'J, but 1 am not aware that 

 attention had been previously called to this fact in print. Tlieir posi- 

 tion had been jireviously known ; but it is not uniform in all chitons. 

 In some the fenestra) are close to the anus and single on each 

 side ; and it has been stated that the ovary of one side is sometimes 

 abortive. This last 1 have not yet observed in any species which I 

 have dissected. — BaUdin of tlie Essex Institute, vol. vi., Aug. 1874. 



"Boreal and Arctic iSheJls.'" 



We beg to call the attention of our readers to the following commu- 

 nication received from the Secretary to the Smithsonian Institution. 



To the Editors of the Anaals and Magazine of Natural Histonj. 



Smitlisonian Institution, 

 Washington, D. C, March 10, 1875. 



Dear Sirs,— Mr. W. H. Dall has been engaged since 1805, under 

 the auspices of the Smithsonian Institution, in prosecuting researches 

 in regard to the marine invertebrates of the region lying between 

 America and Asia, from latitude 50° to latitude 70° N., including 

 the coasts of Russian America, the Aleutian Islands, Behring Sea 

 and Strait, and the Arctic Ocean north of the Strait. He is now 

 occupied in working up his collections at the Institution, with special 

 reference to correlating the species of the Arctic fauna, and their 

 relation to those of both the Atlantic and Pacific seas. 



The Smithsonian Institution is desirous of obtaining suitable 

 material for his comparisons, especially from the coasts of Greenland, 

 Spitzbergcn, Norway, and Sweden, the northern coast of llussia, and, 

 in general, the boreal seas of Eui-ojie. While any and all marine in- 

 vertebrates wiU be acceptable, Mr, Dall at present is especially anxious 

 to secure, as soon as possible, all the arctic and boreal species of Tuni- 

 cates and of Shells, and especially such as contain the animal, either 

 dry (if Gasteropoda) or preferably in alcohol, and for the commoner 

 species large series and from as many different localities as possible. 



In return for such contributions the Institution offers a series 

 from Mr, Dall's very extensive collections, which will be supplemented, 

 if necessary, by duplicates from the collections of the U,S. Fish Com- 

 mission made on the east coast of the United States, and identified 

 by Prof. A. K. Verrill and other collaborateurs of the Commission. 

 Any valuable specimens which may be lent for examination will 

 be carefully preserved, and returned at as early date as possible. 

 Specimens may be sent through any of the European agents of 

 the Smithsonian Institution. Very respectfully, 



Joseph Henry, Secrelarv S. I. 



