ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 951 



spond to the ctenidia of the archimollusc as Lankester suggested, 

 not only because of their position at the sides of the mouth, but also 

 because of their innervation from the cerebral, and not, like the 

 ctenidia, from the visceral ganglion. 



III. Comparison with Dentalium. — Prof. Grobben supports his 

 views by a morphological comparison of Dentalium, Nautilus, and 

 Sepia. He defends his " orientation " of the body of Dentalium, in 

 which of the two mantle apertures, the larger, through which the 

 foot projects, is turned forwards and downwards, while the narrower 

 lies at the apical pole of the body. The mantle-cavity occurs at the 

 posterior side of the body. He discusses corresponding relations in 

 the course of the alimentary canal, &c, and shows the derivation of 

 the Dentalium shell in a manner comparable to that of Fissurella. In 

 connection with the superior mantle aperture in Dentalium, consider- 

 able space is devoted to the discussion of the origin and development 

 of mantle-cavity and cleft. He supports the derivation of Cephalopod 

 arras from Scaphopod cirri by reference to the tentacles of Nautilus. 

 Each Nautilus tentacle he regards as homologous with a Dibranchiate 

 arm. 



Finally, the derivation of Cephalopods from Pteropods is un- 

 favourably criticized. The indecisiveness of the pabeontological 

 evidence is noted. 



(Esophageal Glands of Octopus.* — M. A. Palliet describes the 

 minute structure of the large glands found in the upper portion of the 

 alimentary canal of Cephalopods. Sections of the glands which re- 

 semble bunches of grapes in appearance, exhibit the following structure. 

 About a fifth of the whole mass is occupied by interstitial tissue 

 which includes round cells in an amorphous matrix, fusiform cells 

 imbedded in fibrillar substance, capillaries, nerve-fibres, and sheaths 

 round the ducts. The excretory canals are very abundant, their 

 lining cells are opaque and striated, while those of the secreting ducts 

 arc clear or dark. The gland is not acinose, but is a ramified, digitate 

 tube, comparable for instance to Brunner's glands on the duodenum 

 of the dog. 



Some of the culs-de-sac are, at their base, filled with very granular, 

 polyhedral cells, which almost close the lumen. Higher up elongated 

 cells occur, without the large granules, but staining darkly with osmic 

 acid. These are probably two states of ferment-producing cells. They 

 occupy the deeper third of the canals. The remaining portion exhibit 

 elongated cup-shaped mucus-cells, not darkened by osmic acid. 



The excretory canals exhibit a curious structure. They are lined 

 by a series of opaque balls in a single layer. Each ball is surrounded 

 by a clear zone, and the whole is imbedded in the opaque substance 

 which lines the canals. The whole band has a striated appearance as 

 in the excretory canals of the salivary glands. The balls themselves 

 are striated. In the clear zone round each ball there is a nucleus, 

 surrounded by a zone of clear protoplasm. A comparison with 

 Nussbaum's researches suggests that the central striated portion 



* Journ. de l'Anat. et de la Physiol., xxii. (1886) pp. 398-401 (1 pi.). 



