Hogg, on the Lingual Membrane of Molhisca. 103 



and had not a prehensile collar, with its sharp spines, been 

 found in connection with it, we might without hesitation 

 have pronounced them carnivorous. JEgirus is furnished 

 with an additional horny jaw or plate, situated in the buccal 

 lip ; it acts in the same way as does the corneous jaw 

 of Limax. The tongue of Doris tubercidata is broad, 

 and covered over with nineteen rows of simple recurved 

 teeth. The median tooth appears to be deficient, while the 

 laterals are numerous, about seventy on each side, hooked 

 or recurved, increasing in size as they leave the median line. 



Eolis papulosa (fig. 40) the odontofore is narrow, and fur- 

 nished with a longitudinal series of teeth, curiously articulated, 

 bearing a striking resemblance to the spinal column of 

 vertebrate animals. And thus do we find the structure of 

 the odontofore assisting greatly in our knowledge of the 

 affinities of these animals ; it is, indeed, surprising how the 

 characteristics of a shell (perhaps before misunderstood) 

 concur to bear out the affinities indicated by the odontofore ; 

 and when the mandible can be made available as an addi- 

 tional distinctive aid to investigation, we may hope at no 

 distant day to discover " the origin of species " among the 

 mollusca. 



Many other peculiarities will be observed upon making 

 a close examination and careful comparison of the numerous 

 tongues represented in the plates accompanying this paper. 



The Woodwardian collection of lingual membranes has 

 not only furnished materials for the observations submitted 

 to your notice, but has also suggested practical points which 

 I am sure will be of interest, if not of value, to collectors of 

 specimens. The late Mr. J. P. Woodward, assisted by friends, 

 collected upwards of two hundred specimens. Among his 

 contributors I find the names of K,. M'Andrew, J. W. Wilton, 

 L. Barrett, Dr. Troschel, Hugh Owen, J. Leckenby, Dr. 

 Ravenel of South Carolina, &c. The specimens are mounted 

 in various media, such as the experience pf the preparer and 

 mounter seems to have suggested — Canada balsam, glycerine, 



Pauceri, '6i per cent, of free sulphuric anhydride in the same secretion, as 

 well as sulphuric acid in four species of Tritonium, — in a Cassis, two 

 Murices, and an Aplpia. This discovery, apart from its special interest, 

 offers a partial explanation of the facility with which the boring gasteropod 

 seems to penetrate shells, &c. 



On taking the small quantities at my command of both solid and fluid 

 portions of carnivorous and phytivorous mollusca, and digesting in ether, 

 evaporating and submitting them to Browning's direct-vision microspectro- 

 scope, I obtained indications of Chlorophyll and Cruorine. No doubt, if 

 larger quantities of each were taken, and the residue carefully heated, posi- 

 tive bands would appear in the spectrum. 



