ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 365 



Mollusca. 



Gustatory Bulbs of Molluscs.* — W. Flemming discusses the 

 nature of tlie organs found on the tentacles of various molluscs 

 which have the structure of gustatory bulbs. On the tentacles and 

 marginal tactile organs of Trochus cinerarius the author has observed 

 closely packed long papillae, which are also scattered over the edge of the 

 mantle and the head. In a fresh papilla there is an indistinct internal 

 longitudinal striation which, on isolation, is seen to correspond to a 

 central bundle of long cells ; these cells are provided with fine short 

 cilia, of which there are several on each cell ; by far the largest part 

 of the papilla is composed of epithelial cells. Gold-staining reveals 

 the presence of primary nerves giving off a large number of lateral 

 branches, sufficient apparently to supply each papilla with a terminal 

 nerve. Structures of a similar character are to be found among the 

 Lamellibranchiata. 



The organs just described may, it is clear, be fairly compared with 

 those which F. E. Schulze has spoken of as the gustatory organs of 

 tadpoles, which are, likewise, freely projecting epithelial papillse ; 

 nor do these, except in their position, differ essentially from the gusta- 

 tory bulbs of mammals ; the only important difference between the 

 organs of the Mollusca and the Vertebrata is to be found in the fact 

 that in the former the end-hairs of the central sensory cells project 

 freely, while in the latter they still lie within the bulb ; as, however, 

 the ends of the hairs are, even in the latter case, in direct contact 

 with the surrounding fluid, the difference is not one of much im- 

 portance. 



Although it is not certain that the end-organs described as existing 

 in certain Mollusca have a gustatory function, yet Haller's suggestion 

 to this effect has much to recommend it. From the point of view of 

 developmental doctrines it is certainly of interest to observe that in 

 some forms there are specific sensory organs at the very points where 

 in most, and even in the most closely allied forms, there are only scat- 

 tered ciliated cells. It is for the zoologist to extend the area of these 

 observations. 



Morphology of the Eenal Organs and Coelom of Cephalopoda.f 



— C. Grobben first deals with Sepia officinalis, then with Eledone 

 moschata, and next treats of Nautilus in a comparative way. As 

 is well known, the last-named cephalopod has four instead of two 

 renal sacs, but it is not yet certain whether this arrangement is the 

 more primitive or not. Those who regard Nautilus as phylogenetically 

 the more ancient form would be naturally inclined towards the former 

 view ; against this, however, there are certain facts to which Ihering 

 has already directed attention. That anatomist has pointed out that 

 the anterior renal sac has no connection with the coelom, and that, 

 therefore, it is a structure which has not been reduced in the other or 

 dibranchiate Cephalopoda ; Grobben now suggests that it is an offshoot 

 of the primitively simple, and in Nautilus posteriorly placed, kidney ; 



* Arch. f. Mikr. Anat., xxiii. (1884) pp. 141-7 (1 pi.), 

 t Arbeit. Zool. Inst. Wien, v. (1883) pp. 179-252 (3 pis.). 



