BOOKS RECEIVED.- 



A Monograph of the Land and Freshwater Mollusca of the 

 British Isles. Part IV. By J. W. Taylor, F.L.S. Taylor 

 Bros., Leeds, pp. 193-256. Figs. 378-513. 



The first fifteen pages of the present part complete the detailed 

 " Morphologv of the External Organs " alluded to in our last review, 

 by finishing an account of modifications of the foot and pedal glands, and by 

 giving an exhaustive description of the mantle and body region, including a 

 brief but clear explanation of \isceral torsion. 



"Fig. 385." Sphacrium rivicola (Leach) shewing the subreptatory burrowing 

 or crawling foot. 



The remainder of the part deals with the " Internal Organization " in 

 a similar way, but does not complete it as was expected. f The nervous 

 system is first described in great detail. We give two illustrations which 

 (with others) have been kindly lent by the author (Figs. 424 and 425), that 

 shew types of nerve collar which respectively do, and do not allow the 

 passage of the buccal mass through them. 



" Fig. 424." Semi - schematic view of the 

 prosoma of Limax, shewing the arrangement 

 of the ganglia, nerves and other organs, and their 

 relation to the protrusible and retractile buccal 

 bulb, X 3 (after Pelseneer). 



a., abdominal ganglia : c, cerebral ganglia, 

 with the infero-posterior buccal ganglia, and 

 also shewing nerve prolongations to the eyes, 

 rhinophores, labial lobes, Semper's lobes, etc. ; 

 o.e., oesophagus ; p., pedal ganglia ; p.^l., pedal 

 gla d ; pi., pleural ganglia ; s./., Semper's lobes ; 

 «., anterior aorta ; v., visceral or pallial ganglia. 



Very many interesting facts are brought forward with regard to the 

 powers of smell, vision and hearing ; in fact, this portion of the work 

 seems to be of a most useful nature, and tends to overcome our desire for the 

 beginning of the systematic portion of the work. 



* For the present only books received by the Editor will be noted. 

 t See part I. of the Monograph, p. 2 of the cover. 



"Fig. 425." The buccal bulb 

 ofSiiccinea putris (L), shewing the 

 close constriction of the cerebro- 

 visceral nerve ring around the 

 oesophagus, cephalic retractors 

 and salivary ducts owing to the 

 shortening of the cerebro-pleural 

 connectives which totally pre- 

 vents the retraction of the 

 buccal bulb through the nerve 

 ring X S, and organs. 



