331 
of Dipnoan Fishes. 
slight aggregations of nuclei and protoplasm in the mesoblast 
internal and slightly dorsal to the archinephric duct. It is re- 
markable that the tubules, at first strictly metameric, become at 
a very early stage increased in number so as to be about twice 
as numerous as the myomeres in the same region. Each tubule 
rudiment assumes the form of a (j, the longer limb coming into 
contact with the wall of the archinephric duct. About stage 31 
a lumen appears in the better developed rudiments, which thus 
become tubular. The outer end of the tubule opens into the 
archinephric duct. The inner end, the end of the shorter limb of 
the (j, expands, becomes thin walled and soon becomes dilated to 
form a chamber which in a transverse section appears nearly as 
large as the section of the archinephric duct. The cavity in 
question is the rudiment of the Malpighian capsule, and thus the 
capsular coelom in Lepidosiren develops secondarily as a cavity in 
the mesoblast, quite distinct from the perivisceral cavity. In 
Lepidosiren peritoneal funnels connected with the mesonephros 
do not exist at any period. For some time there is no glomerulus 
projecting into the capsule, but by stage 35 the glomerular pro- 
jection is quite distinct. 
Testicular network of Dipnoi. 
The existence of a connexion between testis and mesonephros 
was first established by Ehlers for Lepidosiren. Semon has recently 
chronicled the discovery of spermatozoa in the Malpighian cap- 
sules of Ceratodus — pointing to a connexion in that Dipnoan. 
I have myself described the testicular kidney connexion in Pro- 
topterus, and I have also worked out in detail and figured for the 
first time the precise relations in the adult male Lepidosiren. 
These relations may be shortly summarised as follows : 
In Lepidosiren the very much elongated testis is divided into 
two regions — a larger formative region somewhat cylindrical in 
shape and lying immediately ventral to the mesonephros, and a 
shorter, much narrower, vesicular region which, imbedded in 
a sheath of dense connective tissue, similarly lies ventral to and 
closely apposed to the ventral edge of the kidney. The con- 
nexions of testis with kidney are limited to the posterior portion 
of* the vesicular region, whence about half-a-dozen vasa efferentia 
pass into the substance of the kidney. Here they break up into 
branches which open into the cavities of Malpighian capsules. 
From these the spermatozoa reach the cloaca by the kidney tubules 
and Wolffian duct. 
In Protopterus essentially similar conditions hold, modified 
slightly by the fact that in the fully-developed Protopterus the 
kidneys and also the vesicular portions of the testes have become 
