241 
different functions, which in no way ever become 
modified so as to replace one another’). 
6) It has been suggested by both Donrn and LANKESTER that the 
Cyclostoma are a degenerate class, and more recently borne out 
by the researches of SANDERS on the brain and nervous system. 
If this view is correct, then we may possibly regard the “white- 
bodies” of RATHKE as degenerate suprarenal bodies, from the fact 
of the presence of the peculiar nucleated spindle-cells. With equal 
probability they might also be said to represent the thymus, seeing 
that they are larger in young forms than in the adult. 
7) Up to the present we are inclined to regard the 
Suprarenals as paired bodies first appearing in 
Fishes and increasing in importance as we ascend 
the scale, and not in any sense as the remains ofa 
structure with a past history. One or other, or both 
of the constituent parts is present in all Vertebrates, 
with the possible exceptions of Cyclostomaand Dipnoi. 
Suprarenals, Pronephros, 
Cortex. | Medulla. | 
Cyclostoma. hihi degenerate Present in Myxine and 
Bdellostoma, absent 
in Petromyzon. 
| 
Elasmobranchii. | Interrenal. | Paired suprarenals,| Absent in adult. 
Holocephala. do. | do. | do. 
Ganoidei. Suprarenals in | Apparently absent.| Lymphatic. 
kidney. 
Teleostei. oocyte isupraronals on do. Lymphatic (excepting in 
kidney. Lophius, Dactylo- 
pterus, Fierasfer, 
Orthagoriscus, 
Mora, and the Ma- 
| eruidae?). 
Dipnoi. 
No suprarenals as yet described. Peri-| Absent in adult. 
renal large-celled adenoid tissue ? ?). 
wish to express any definite opinion on the point, but from a study of 
the anatomy and histology in adult specimens we consider that MrHat- 
Kovics’ view is the more likely to be correct. 
1) Grosexix’s (Zool. Anz., Bd. 8, 1885, p. 605—-611) views and Dr. 
VINCENT’s do not agree, but even supposing the former is correct, the 
evidence is still insufficient, 
2) Vincent, Proc. Bgham. N. H. and Phil. Soc., 1896, Vol. 10. 
17 
