1893.] On the Genera of the Dipnoi Dipneumones. 929 
remains entirely within the intestinal wall lying between the 
mucous membrane, of which it is an outgrowth, and the mus- 
cular coat of the gut and it thus represents a very early stage 
in the ontogency of the organ as it is developed in other ani- 
mals. 
Professor Parker states that the spiral valve in Lepidosiren 
annectens makes 6 or 7 turns. I found in all the specimens 
studied, and the point was we examined, that the num- 
ber was uniformly eight. 
Our author attributes the statement to me that Lepidosiren 
lacks a distinct muscular coat to its stomach, and that in the 
intestine the musculature is only slightly developed. 
On page 491 of my “ Beitrüge" I state: “Sowohl bei Cera- 
todus als bei Lepidosiren sind die Wände des Vorderdarmes 
auffallend dünn. Bei der maceration traten zwei deutliche 
Lagen von Muskelzellen hervor. Sie reprüsentiren die Längs- 
und die Ring muskulater der hóheren Wirbelthiere und sind 
sehr ähnlich der Muskelelementen der Cyclostomen, etc." 
The passage which Parker alighted upon to misconstrue by 
taking it away from its context, reads as follows: * Bei Cera- 
todus ist das Magenende veshültnissmüssig viel weiter als bei 
Lepidosiren (italics inserted here). Eine deutliche Muskulatur 
fehlt, doch sind zahlreiche spindelfórmige Muskelzellen durch 
das ganze Bindegewebe der submucosa zerstreut.” 
Parker states that he failed to find the lobulation of the kid- 
neys in Protopterus as described by me for the older individuals. 
My observations were made on a specimen 42 em. long. The 
lobules were well-marked, but not so numerous or so sharply 
defined as in Ceratodus. He concurs in my statement that the 
so-called male organs of writers previous to 1884, were, in all 
probability, only immature female organs. Parker describes - 
the presence of two vibratile filaments in the spermatozoan of 
Protopterus and considers this condition unique among verte- 
brates. I have observed the same structure in ripe sperma- 
tozoan of Rhinoptera bonasus. My observations were made on 
July 13, 1889, at the Marine Biological Laboratory, and it was 
found that the apparently single-headed, double-tailed sperm- 
atozoan resolved itself into a simple, straight filament, possess- 
