46 SUMMARY OF CURRENT RESEARCHES RELATING TO 



New Cranial Nerve in Selachians.* — W. A. Locy returns to a 

 nerve which he discovered in 1899, and gives fresh details as to its 

 history. In arises in young embryos of Squalus and other Selachians 

 on the dorsal summit of the forebrain on each side of the neuropore, 

 in close connexion with elements of the disappearing neural crest. Its 

 fibres are formed slightly before those of the olfactory nerve, and 

 proceed to the olfactory epithelium. Pinkus has observed a similar 

 nerve in Protopterus, and Allis in Anita. Even if it be one of the 

 olfactory bundles in an unusual position, its separateness in origin and 

 differences from all other olfactory radices would still justify the term 

 " new nerve." It has been looked for in vain in amphibians and 

 Tcleosts. 



History of the Eye of Amblyopsis.f — Carl H. Eigenmann dis- 

 cusses the whole story of the eyes of this blind fish. " In Amblyopsis, 

 which carries its young in its gill cavity, we are undoubtedly dealing with 

 an animal in which the eyes are useless in the young as well as in the 

 adult, and in which they became totally useless in the young at the same 

 time that they became totally useless in the adult, that is, at the time 

 when the species took up permanent quarters in the caves. Do the eyes 

 in this case repeat the phylogenic history of the eye, or have the eyes 

 in the embryo degenerated in proportion to their degeneration in the 

 adult ? The question is whether a perfect or better eye is produced to 

 be finally metamorphosed into the condition found in the adult, or 

 whether the development of the eye is direct." 



Eigenmann's results show that the foundations of the eye are 

 normally laid in the embryo, but that the superstructure, instead of con- 

 tinuing the plan with new material, completes it out of the material 

 provided for the foundations, and that, in fact, not even all of this (lens) 

 material enters into the structure of the adult eye. " The development 

 of the foundations of the eye are phylogenic, the stages beyond the 

 foundations are direct." 



Segmental Veins in Amphioxus.J— Boris Zarnik refers to Burc- 

 hardt's discovery (1000) of the ductus Cuvieri in the lancelet, and points 

 out that behind this there are several variable vessels, which display a 

 metameric arrangement. These are transverse segmental veins, and the 

 ductus Cuvieri may be regarded as a specialisation of one of these. They 

 are very variable, and must be regarded as rudimentary structures. In 

 this respect, as in many others, Amphioxus is intermediate between the 

 Craniota and the Annelids. The author gives an account of the general 

 circulatory system of the lancelet. 



Experiments on Ciliary Movements.? — L. Launoy finds that the 

 local application of a solution of chlorhydrate of amylein has a tonic 

 action upon the vibratile cilia of the pharyngeal membrane of the frog. 

 It is, however, temporary, and is succeeded by an adynamic state. 



* Mark Armiv. Vol., 1903, pp. 39-55 (2 pis.). 

 t Tom. cit., pp. 167-204 (4 pis.). 



* Anat. Anzeig.. xxiv. (1904) pp. G09-30 (1 pi. nnd 7 figs.) 

 § Comptes Rendus, exxxix. (1904) pp. 162-5. 



