m 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
least between cerebellum and thalamus) which have become merged in 
the ontogeny of higher forms. There is scarcely any cranial flexure. 
Although the developmental type of Bdellostoma is distinctly mero- 
blastic, it is noteworthy that there appears no trace of a germ-ring ; 
•except in the immediate region of the tail, the somites arise in situ at 
the sides of the neural axis. 
The early appearance in each segment of pronephric tubules, similar 
to each other in essential characters, demonstrates, as Price has shown, 
that the entire excretory system of Myxinoids must, from the stand- 
point of ontogeny, be regarded as univalent. If we accept, therefore, 
Spengel’s criticisms of the results of Semon on the morphology of the 
excretory system in Myxine , we must nevertheless admit Semon’s a 
priori view as to its homology as a pronephros. 
Supra-Renal Capsules.* — Dr. Swale Vincent finds in a recent paper 
by E. Huot a reason for restating the case in regard to supra-renal and 
inter-renal bodies. The cortex and medulla of the supra-renal in 
Mammals correspond respectively to the inter-renal and paired supra- 
renal bodies of Elasmobranchs. In Teleosteans the known supra-renal 
bodies (corpuscles of Stannius) appear to consist solely of cortex, the 
medullary substance being absent. In the higher Vertebrates the two 
parts occur in combination. 
Eggs and Larvae of Marine Fishes.f — Fabre-Domergue and E. 
Bietrix have made an extensive series of observations on various points 
connected with marine pisciculture. They begin with methods of keep- 
ing adult mature fish in captivity, the turbot being chosen as the subject 
for experimentation. The main difficulty is that there supervenes upon 
capture a longer or shorter period during which the fish take no food 
whatever, while the rate of mortality is exceedingly heavy. Dissection 
showed that the refusal of food is not merely due to lack of appetite, but 
that the physiology of nutrition is profoundly modified, the process of 
digestion being temporarily suspended. Thus food taken immediately 
before capture remains undigested in the gut until death occurs. This 
period of acclimatisation is much shorter and less fatal in young fish, 
which should therefore only be chosen. The observations upon eggs and 
larvae were conducted on a large series of forms. It was found that 
larvae respectively with and without eye-pigment behaved very differently 
under the action of light. The former were markedly actinotropic, 
collecting in the area of greatest illumination, and following a moving 
light, while the latter showed themselves indifferent to light. The 
authors lay most stress, however, upon their observations on larvae in the 
critical stage, namely that which intervenes between the absorption of 
the yolk and the assumption of the adult form. Such larvae cannot be 
induced to take food in captivity, and, save in rare and isolated instances, 
invariably die if not set free. In consequence the habit at marine 
stations has been to liberate the larvae before the disappearance of the 
yolk-sac, and to assume that it is the lack of suitable food which is 
the cause of death. The authors made numerous examinations of the 
intestinal contents in larvae caught in the open sea, and supplied their 
* Anat. Anzcig., xiv. (1897) pp. 151-2. 
f Ann. Sci. Nat. (Zool.), iv. (1897) pp. 151-220 (18 figs.). 
