THE AMERICAN NATURALIST. [Vol. XXXVIII. 



course it may be impossible to demonstrate this, in which case the 

 present classification may very well be allowed to remain. The 

 genus ffeterognaihus^ Schmarda, is applicable to the species having 

 the toes equal — part of the present Diurella. The author admits 

 that this group may be thought worthy of separation, but he does not 

 notice that the name belongs properly to a genus of fishes, the latter 

 having five years' priority. If the equal-toed species deserve a 

 generic name, a new one will have to be proposed. 



Looking over the paper, one notices the absence of any records 

 from the region west of the great plains, as well as from other great 

 regions. It is to be hoped that students will arise in some of the 

 neglected parts of the country, now that the study is made com- 

 paratively easy. 



T. D. A. C. 



Gardiner's Reports on the Fauna and Geography of the Mal- 

 dive and Laccadive Archipelagoes have now begun a second vol- 

 ume. The First Part contains an account of the Alcyonaria, by 

 Hickson and E. M. Pratt, of the nudibranchs by Sir Charles Eliot, of 

 Sponge crabs by Borradaile, of Lagoon Deposits by Gardiner and 

 on a Land Planarian by Laidlaw. The Part contains nine litho- 

 graphed plates. 



Hickson discusses the remarkable variability of the Alcyonaria and 

 concludes that either they constitute a large number of closely similar 

 species or else one species capable of extraordinary variation in cir- 

 cumstances that are approximately identical. For practical purposes 

 the author regards those variations as species which are discontinuous. 

 Hickson finds that the form and mode of branching are unreliable 

 criteria of any species because they vary with accidental variations in 

 environment and the presence of gall producing Crustacea that reside 

 in the branches. 



Eliot's Report contains many interesting general data, concerning 

 swimming Hexabranchidae, hidden but highly colored Doridid^e, self- 

 mutilating Dicodoris, a Phyllid that secretes a liquid with disagreea- 

 ble smell and others. 



C. B. D. 



Position of the Gordiacea. — Montgomery concludes ^ from a 

 study of the adults that the Gordiacea agree with the Nematoda in 

 only the tubular gmitalia and their opening into the cloaca. They 

 ' Zoolog. Jahrbiicher Abth. f. anat. xviii 1903. 



