SCIENCE-GOSSIP. 



i8i 



The book is well | rinted, and handsomely bound in 

 cloth, and our most serious criticism would be its 



issue, as a scientific I k. without any date on the 



title-page. A book like this contains a wealth of 



suggestion that should help to make many a dilet- 

 tante owner of a microscope an earnest student of 

 nature. — F. S. S. 



A Monograph of l In 1 Land and Freslunsater Mol- 

 hisca of the British Islet. By John W. Taylob, 

 F.L.S. ' Part VI. pp. 321-384. 10£ in. x 6£ in., with 



108 illustrations. (Leeds: Taylor Eros. 1900.) 6s. 

 With the present instalment Mr. Taylor Urines 

 to an end the consideration of the shells and soft 

 parts of the molluscs. It appears, however, from 

 an announcement to the subscribers, that yet an- 

 other part will appear before volume I. is completed. 

 In this will be discussed the important subjects of 

 distribution in time and space, as well as the para- 

 sites attacking molluscs and the uses of the latter 

 to mankind. The pages which we have here to 

 consider touch upon some of the most interesting 

 points in connection with mollusca. Under the 



adductor muscles, but it maj be pointed out that 

 the investigations of Mr. IS. Pace upon the pearl 

 oyster poinl to the fact that abnormal conditions 

 in the mollusc itself play a much more important 



part in the production of pearls. .Mr. Pace was 

 able to infect healthy oysters and so obtain pearls 

 from them. The biological remarks upon colora- 

 tion, though little fault can be found with them, 

 demonstrate how much work there remains to be 

 done upon this fascinating part of the subject. In 

 other places Mr. Taylor discusses molluscs gene- 

 rally; here, however, and perhaps wisely, he con- 

 fines his attention to the species strictly includi d 

 under the title of his monograph. Excretory 

 organs, lymphatic glands, and the muscular systi m 

 are described and illustrated. Finally, the repro- 

 ductive organs and development bring structural 

 considerations to a close. Among the illustrations 

 kindly lent by Mr. Taylor, we show the love-darts 

 and the annulus which supported one, in a speci- 

 men of Helix fifpi'Tsti. J-Mnne species spend a con- 

 siderable time over their courtship, and one of our 

 pictures shows the love-making of a sinistral and a 



The courting of a siuistral and a dextral specimen of Helix asperm. 

 (From Taylor's " Monograph of Land and Freshwater Shells." I 



heading of glands and secretions the attachment 

 threads (byssus) are described ; the embryonic 



a. Love-dart of Helix hortensis. 



b. Love-dart of Helicigona lapicida, 



shell is mentioned, while the three pages devoted 

 to pearls are welcome reading. The author alludes 

 to pathological causes giving rise to pearls in the 



dextral example of the common snail, //. <7Sj)cr.«t. 

 From one's personal observation one would say 

 that important parts of the drawing illustrating 

 the paiiing of iAmax maxirnvs require to have 

 more detail introduced, and here one misses the 



,-. The annulns of ;i dart from Helix aspt rta. 

 d. Egg-capsules of Valvata crisiata. 



series of sketches by Mr. Lionel Adams in the 

 "Journal of Conchology " in 1898, leading up to 

 the final position, alone depicted by Mr. Taylor. 

 Numerous figures elucidate the remarks upon 

 development, "which, if we except a ] age and a half 

 of supplementary bibliography, bring to a close 

 a number not descending everywhere perhaps into 

 such detail as in its predecessors, yet well worthy 

 to take its place with them.— If. X. II . 



