242 



SCIENCE-GOSSIP. 



I think the fact that birds fed with carbonate of iron 

 have the colour of their plumage intensified, instead 

 •of altered, is explained on the supposition that the 

 different colours of, for instance, a fowl are all formed 

 by pigments containing iron in some form, not neces- 

 sarily always the carbonate. There is nothing unlikely 

 in this supposition, as iron is known to exist in various 

 hues. I have found the colour of molluscs' shells, 



whether black, orange, red, or blue, as in mussels, 

 caused by it. Carbonate of iron furnishes the bird 

 with an increased supply of this element to aid in the 

 formation of the different pigments, and so they are 

 all intensified. I do not say, however, that the 

 colours of all birds are caused by iron, and I will refer 

 to this again. 



( To he continued. ) 



MONOGRAPH OF BRITISH LAND SHELLS. 



A LITTLE more than five years ago Mr. J. W. 

 Taylor issued the first carefully executed part 

 of his monograph on our non-marine molluscs. (') 

 Since that time others have appeared at increasing 

 intervals, until half way through last November the 

 subscribers received the fifth instalment, some nine- 

 teen months after its predecessor. Labours of love 

 have a tendency to claim a "sweetness long drawn 

 out," a fact which in the present instance, amateurs 

 of the mollusca must unanimously regret. One 

 fancies too, that there are some who are sorry that 

 the first volume has not been as it was hoped " easily 

 completed in four parts," and that the fifth one still 

 leaves it unfin- 

 ished. It is easy 

 to imagine the 

 shell collector, 

 the student of 

 distribution, and 

 the stickler for 

 priority, who 

 would be made 

 better naturalists 

 by a little ana- 

 tomical know- 

 ledge, saying 

 that they were 

 being given too 

 large a dose, or 

 that much of this 



information might have found a place under ordinal, 

 generic, and possibly specific headings. Other more 

 biological readers would probably echo the latter 

 sentiment and might expect to see Mr. Taylor's time 

 devoted to the systematic portion of the work. They 

 would no doubt be prepared to forego some of the 

 author's own finely made drawings, and many of his 

 clear interpretations of anatomists' figures, which 

 they are already familiar with, or have at their elbow, 

 in favour of more representations of the animals 

 themselves, their habits, and surroundings. 

 As, however, the monograph is not intended 

 for any one class of students, and as pure 

 conchology has hitherto reigned supreme in our 

 books on land and freshwater shells, from an 

 unbiassed point of view, it must be allowed that Mr. 



Teeth from the Radula of Tesiacella lialiotidea . 



Taylor is not only courageous, but really in the right. 

 If the various species be treated in the same thorough 

 way as the anatomy, the pages devoted to the latter 

 will by no means seem out of proportion ; but one 

 must be not accused of levity for pointing out that 

 unless the parts be made larger or issued more often, 

 and unless Mr. Taylor avails himself of material 

 assistance in his gigantic task, the present generation 

 will not be able to make full use of the book. 



To turn however to the sixty-four pages which have 

 been recently issued, it is found that the account of 

 the radula which had just been started in Part IV., is 

 continued and finished with considerable complete- 

 ness. Methods 

 of extraction, 

 staining and 

 mounting of this 

 characteristic 

 organ are de- 

 scribed. Mr. 

 Taylor chooses 

 the word 

 odontophore for 

 his own use, 

 which is a pity, 

 jf seeing that it 



has been used 

 to denote the 

 muscle which 

 supports, and 

 brings into action the radula. A classification is tenta- 

 tively made by Mr. Taylor of the radulae of pulmonates. 

 These are divided into those with narrow basal plates to 

 the "teeth" (S tenodontophora), and those in which 

 these are broad (Eurydontophora). Three sub-head- 

 ings are given of the first; forms with "sickle- 

 shaped," or as Mr. Taylor calls them, " prickle- 

 shaped ' teeth,' " are not represented among our land 

 and freshwater snails; "arrow-shaped," or as one 

 would preferably call them "fish hook-like 

 ' teeth,' " only occur among our worm-eating slugs 

 (Testacellae) and by the courtesy of the author 

 his figure illustrating these is reproduced. The 

 drawing is evidently from the specimen previously 

 mentioned in a paper by Mr. Taylor (Journal of 

 Conchology, 1888, p. 341), and the number of teeth 



