TRANSACTIONS OF THE SECTIONS. 133 



lesser curvature. The muscular wall is ver}' thick, and the mucous membrane of a 

 peculiar appearance. The valvula pj'lori is wanting in many animals, and is re- 

 placed by the strong and broad layer of circular muscular fibres in the antrum 

 pylori near the beginning of the duodenum. In some animals a little groove exists 

 in the great curvature of the antrum, behind the passage into the duodenum. The 

 border of this forms a thick semilunar fold, somewhat resembling a part of the 

 valvula pylori. Professor Retzius regards the third stomach in the ventricle of the 

 Porpoise (D. pJioccena) as the same with the antrum pylori. The fourth stomach, 

 which Cuvier describes, in the ventricle of Delphinus, is only a globular dilatation 

 of the first part of the duodenum, iir which part the biliarj' duct opens. Professoi* 

 Retzius has found a corresponding dilatation in the first part of the duodenum in 

 man and several mammals, and proposes to call it antrum or atrium duodeni. In 

 man, the first part of the duodenum has no plicee conniventes, as several anatomists 

 have long ago remarked (Quain, Hyrtl). The author illustrated this communicatioa 

 with a rich collection of drawings. 



On the peculiar development of the Vermis Cerebelli in the Albatros (Dio- 

 medea exulans). By Professor Retzius, Stockholm. 



Dr. John Kinberg, Zoologist and first Surgeon of His Majesty's frigate ' Eugenie,' 

 during her voyage in the Pacific Ocean, had occasion to prepare a perfectly fresh 

 brain of an Albatros. The brain was immediately put in strong spirit, brought 

 home, and presented to the Anatomical Museum of the Royal Caroline Institute, 

 Prof. Retzius had remarked that the cerebellum of this specimen presented quite a 

 peculiar development. It was flattened on both sides, with very little protuberance 

 at the base of each side, and, as in birds in general, the central part or vermis 

 much developed, but in this more than in any other known bird's encephalon. 

 This middle part, forming the whole cerebellum, projects like a fan behind both 

 hemispheres over the medulla oblongata, being more than one-third raised over the 

 level of the highest points of the hemispheres. Professor Retzius counted on the 

 edge twenty-eight tongues or foliated gyri, proceeding from two branches, one of 

 which turns forward and the other backwards ; the whole having some likeness to 

 a cock's comb. Professor Retzius had examined the brains of many birds, but 

 never found anything like this, and supposed that this peculiar development of the 

 middle part might stand in some proper relation to the great perfection of the 

 flight of the Albatros. This bird lives, as we know, only in the vast ocean ; 

 dividing his solitary life between the air and the waves, without approaching the 

 shores by many miles' distance. Mariners meet with him in these regions, accom- 

 panying the ships for whole days without ever resting on the waves, and often 

 without any visible movement of his large and powerful wings. And if it be as 

 Professor Flourens regards it, one of the functions of the cerebellum to assist in the 

 combination of the action of the separate muscles for motion, this combination 

 must be so much more necessary the more perfect are the movements. In this 

 bird, the strong, continuous, tranquil flight seems to occur in its highest degree, 

 and, as Professor Retzius believes, depends on the peculiar development of the 

 Vermis cerebelli. 



On the Fornix Cerebri in Man, Mammals, and other Vertebrata. 

 By Professor Retzius, Stockholm. 



The shape of the fornix in the completely formed human brain gives us only an 

 imperfect idea of the proper nature of this part. Professor Eschricht of Copen- 

 hagen has, in his excellent Manual of Physiology (Haandbog d. Physiologien), 

 given an excellent description of the first formation of the fornix, as the inner and 

 lower margin of the two original hemispherical vesicles, embracing the trunk or the 

 arms of the cerebrum. This is the point of view from which the further develop- 

 ment of this part ought to be considered. This view, of which we owe the first 

 key to Tiedemann, had been adopted by Prof. Retzius in an original paper on the for- 



