194 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



verify, except those of the short resume we have given 

 from Patten with regard to the development. 



It is unnecessary to refer to the many authors whose 

 works we have had to consult, but we wish to acknowledge 

 our special indebtedness to the researches and theories 

 of Ray Lankester, J. W. Spengel, Pelseneer, Remy 

 Perrier, Beta Ilaller, Lacaze Duthiers, Boutan, Grobben, 

 and Patten. 



The matter which we believe to be new includes the 

 following chief points : — 



(1) A lateral glandular streak has been found along 

 each side of the foot of young specimens, resembling that 

 found in Nacella and its allies. 



(2) A muscular zone (which we name the internal 

 pailial muscle) has been found extending in the mantle 

 between the tips of the shell muscle. 



(3) The structure of the Crop, and inferences drawn 

 therefrom as to special torsion of the viscera of Docoglossa 

 during consolidation of the visceral hump. 



(4) The respiratory function of the nuchal cavity as 

 regards damp air. 



(5) Discussion of the evolution of the present topo- 

 graphical relations of rectum, kidneys, pericardium, and 

 heart. 



(6) Details of mantle innervation and pailial tentacles. 

 Our best thanks are due to Professor W. A. Ilerdman, 



D.Sc, F.P.S., the Editor of this series, for his general 

 advice and special suggestions, and to Prof. J. Travis 

 Jenkins, D.Sc, Ph.D., late of Aberystwyth, for working 

 out several intricate details of mantle innervation as well 

 as other points. The greater number of the drawings are 

 original, but a few are based on those given in Lankester's 

 article " Mollusca," in the Encyclopaedia Britannica (9th 

 edition), and those of the development are after Patten. 



