1893] NOTES A XI) COMMENTS 85 



the A. Jiortensis group is the lower portion of the free oviduct much 

 larger and more globose than the upper. Again, in the paper, the 

 validity of A. fuscus, externally very much like A. svbfuscus, is 

 admitted by Mr Collinge who previously rejected it. This is not 

 to be wondered at since, in another paper on four species of the 

 same genus, published about the same time in the Journal of 

 Malacology (vol. vi., pp. 7-10, pi. ii.), almost the only evidence of 

 external difference between A. empirieorum, A. ater, and A. lusi- 

 tanicus given by Mr Collinge is a short series of measurements 

 pointing to the fact that the second species is larger than the first. 



Of course it is probable that our islands contain more species 

 of Arion than many of us used to imagine, and Mr Collinge has done 

 much to arouse us to the truth about them ; but, before all the 

 species which he and his continental friends would give us are 

 recognised by thinking malacologists, still more careful and detailed 

 work must be done upon the genus. We have been so busily 

 criticising the weak points in the paper that we have only hinted, 

 by quoting a few figures, at the prodigious amount of work which it 

 must have entailed. There only remains for us to express the hope 

 that other workers will come forward and supplement what is a 

 valuable contribution, from an anatomical point of view, to our 

 knowledge of the genus Arion. 



In the other paper we have " the description of two new species 

 of slugs of the genus Parmarion from Borneo" (Proc. Zool. Soc, 

 1897, pp. 778-781, pi. xliv.). One of these the author considers 

 intermediate between the genus in which lie places it, and Micro- 

 parmarion ; in fact it leads Mr Collinge to the conclusion that no 

 line can rightly be drawn between the two genera. 



American Isopods 



Mr J. E. Benedict on March 24 published a paper on "The 

 Arcturidae in the U.S. National Museum " {Proc. Biol. Soc. Wash- 

 ington, vol. xii., pp. 41-51), in which there are several interesting- 

 features. He describes eight new species, and of each of them 

 gives a good and intelligible ' habitus-figure,' an adjunct without 

 which the most lucid description oi a new form is usually difficult 

 and wearisome reading. Within the last twelve years the number 

 of species in the genus Archtrus has been raised from five to 

 twenty-five. Mr Benedict has therefore rendered a kindly service 

 by supplying a key to this rapidly increasing group. As often 

 happens, when new species appear, some of the old generic dis- 

 tinctions have to disappear. Mr Benedict finds, for example, that 

 in some species of Arctwus the fingers are not simple, but bi- 

 ungulate as they are in Astacillo. It appears, too, from his de- 

 scriptions that Arctv.rus cannot invariably be distinguished from 



