546 JOTTINGS FROM THE BIOLOGICAL LABORATORY. 



surface (fig. 2) has the appearance of a minute honeycomb, owing 

 to its being covered over with numerous rows of minute apertures, 

 arranged with the greatest regularity. 



On the free flap of the 3rd tentacle covering over the 1st, there 

 is to be observed an oval dark patch, which to the naked eye 

 appears minutely tuberculated. When this is examined under a 

 lens (fig. 3) the tubercles are found to be minute elevations, each 

 with a rounded aperture at its summit. Microscopic sections shew 

 the thickened patch to contain numerous branching glands, the 

 ducts of which oj)en at the apertures mentioned. The specimens 

 were not in good order for histological study; but the cells of the 

 glands were found to be full of large rounded granules. 



The remaining portion of the inner series (internal labial 

 tentacles of Owen,* labial tentacular lobe of Kefersteinf) 

 is fully developed only in the female. It consists of a 

 large flattened median lobe, situated posteriorly in immediate 

 contact with the buccal mass. It is divided by a deep 

 median notch into two parts, each of which bears fourteen 

 tentacles. On the middle of its inner surface is an oval patch 

 where the integument is raised up into numerous closely set 

 ridges, which are in series with the tentacles, the most external 

 ridges and the most internal tentacles being scarcely distinguish- 

 able from one another. This ridged bod}'' is referred to by Owen| 

 as probably having an olfactory function, and a similar view is 

 expressed b}'- Ray Lankester.§ Van der Hoeven|| dissents from 

 this and expresses the belief that these folds are "only rudi- 

 mentary digitations completing the circle of the internal labial 

 processes." 



It seems somewhat remarkable that a connection of some kind 

 with the function of reproduction should not earlier have been 

 suggested for the entire inner tentaculiferous lobe with its 



* Memoir on the Pearly Kautilus, 1S32. 



t Bronn's Thierreich, Malacozoa, III. Band, p. 1360. 



t Op. cit. 



§ Zool. Articles from the Encyclopaedia Britannica, Mollusca, p. 137- 



II Trans. Zool. Soc. iv. 



