1008 ELLIOT ROWLAND DOWNING 
Woods Hole, i.e., June to August (LoBianco). A. marina is cap- 
tured with mature eggs and sperm at Woods Hole in the early 
spring, April and May. It is found mature on the English coast 
in the spring (the laminarian variety) and summer (the littoral 
variety) according to Gamble and Ashworth. My specimens of 
sexually mature A. ecaudata were taken at Plymouth in April 
as also were specimens of A. grubil. The latter and A. claparedii 
I found mature at Naplesin May. Both of them have been found 
breeding much earlier there (LoBianco), A. claparedii beginning 
as early as November and continuing throughout the winter and 
spring. By using a haemocytometer I have estimated the num- 
ber of spermatophores per cc. of body fluid in a mature male at 
about forty million. Each spermatophore will average in the 
neighborhood of a thousand sperm. <A good sized male A. cris- 
tata will easily contain twenty-five or more ce. of body fluid, 
that is, a quadrillion sperm, ready to be discharged when fertil- 
ization is to be accomplished. 
DEGENERATION AND PHAGOCYTOSIS 
At the close of the breeding season the body cavity of the male 
contains very little sperm. In only 10 per cent of the September 
specimens of A. .eristata taken at Woods Hole was sperm present 
in any quantity In 60 per cent so little was presen t that it was 
impossible to determine the sex except by sectioning the gonads. 
During August and September the gonad is at its minimum size. 
This I have determined in two ways: First, by macroscopic 
examination. The gonad is apparent on the blood vessel even to 
the naked eye. Examination of the animals throughout the 
year, with record of cases in which the gonad is plainly evident on 
nephridia two to five, shows that in August and September the 
gonads show least frequently. They become plainer during the 
fall, achieve the maximum size from December to March and then 
gradually become smaller again. Second, the same results have 
been reached by making serial sections of nephridia for each month 
and making camera lucida drawings of the largest cross section 
of the gonad as compared with the blood vessel on which it lies. 
The third and fourth nephridia are used preferably for the com- 
