Literary Notices. Ixxxix 



The Brain of Myxine.^ 



The brain was exposed by direct preparation of the hardened 

 subject or by teasing specimens macerated in 20 per cent, nitric acid, 

 a method which often affords beautiful views of the entire brain and 

 connected fibres in minute detail. 



The olfactory organ is so enclosed by annular cartilages that the 

 whole structure is inseparably connected with the brain and is pre- 

 served in the author's figures. The detailed histology is not described 

 while the external features are very carefully and minutely recorded. 

 From the absence of histological data several points are left undecided 

 by the author which could otherwise be readily determined. Thus 

 the author doubtfully identifies a segment of what seems like the mes- 

 encephalon as the cerebellum and is uncertain as to the homologies 

 of the parts of the forebrain. No trace of the mantle of the cere- 

 brum was encouPitered, which gives the author occasion to express 

 much surprise. If we were to attempt an explanation upon the basis 

 of Professor Retzius' figures it would s^'em to he furnished by the rel- 

 atively enormous extent of the olfactory tuber and the compactness 

 of the brain and its obvious conduplication through shortness of the 

 cavity of the cranium. It would appear that the whole free portion 

 of the hemispheres, so far as present at all, is covered by the glomer- 

 ules. In Fig. 7, Plate XXIV, hv seems to be the recessus prasopti- 

 cus, the habena and Meynerts' bundle are very large and the infund- 

 ibulum and hypophysis are m the usual relations. It is not a little 

 remarkable that, although the habenas are all well developed, no trace 

 of the epiphysis was discovered in the dissections or slides. 



The aqueduct is closed anteriorly apparently by the obliteration 

 of its connecton with the third ventricle, which is also closed, with 

 the exception of the infundibulum and recessus praeopticus. 



The structure of the glomerules was studied by the Golgi method 

 and found to correspond with that in vertebrates at large. 



The Rudimentary Jacobson's Org'an of the Crocodile.^ 



Dr. Rose describes the development of the common nasal am- 

 pulla by the closing ot the gum processes and the subsequent separa- 

 ration into two chambers by the union of these processes with each 



' Retzius, G. Das Gehirn und das Auge vohn Myxine ; 3 plates, Biolog. 

 Unters., v. 9, 1593. 



^ Rose, C. Ueber das rudimentrare Jacobsonscche Organ der Crocodile 

 und des Menschen. Anat. Anz., VIII, 14, 15, June, 1893. 



