On the Spermatophores of Octopus Americana. 45 
the aboral portion of the inner tunic, and the whole mass is moved 
together. The sperm thread of which it is composed is never uncoiled. 
This differs entirely in Octopus, where the sperm thread is not closely 
packed, is not inclosed in any kind of membrane, and uncoils as it is 
discharged. 
These questions of structure and speed are of course related to the 
functions they perform. Squid are free-swimming, active creatures, 
and copulation is a very rapid act. Octopus are for the most part 
bottom dwellers and copulation is much more deliberate. The quick 
machine is more complicated, but the two show very similar structure. 
Without knowledge of the past history of these animals it is very 
difficult to arrive at reasons for the formation of such complicated 
structures as these spermatophores to perform functions where simpler 
arrangements would seem to do as well. Doubtless if the past history 
were before us for review we would see clearly why such structures 
have been developed, but in the absence of this history which seems to 
be permanently hidden from us, we can be certain only that the 
complicated machine has been formed and serves its purpose. 
LITERATURE CITED. 
The papers given are the only ones to which it has been necessary 
to refer in this paper. There are many others. 
Drew, G. A. 1919. Sexual activities of the squid, Loligo pealii (Le Sueur). II. The Sper- 
matophore; its structure, ejaculation, andformation. (In press). Jour. Morph., 
vol. 32. 
Racovitza, Emiin-G. 1894a. Sur l’accouplement des quelques Cephalopods Sepiola 
rondeletti (Leach), Rossia macrosoma (d. Ch.), et Octopus vulgaris (Lamarck). 
Comp. Rend. |’Acad. des sci., 118. 
1894b. Notes de Biologie. I. Accouplement et fécondation chez l’Octopus vul- 
garis Lamarck. Arch. d. Zool. Expér. et Gén. (3), 2. 
1894c. Notes de Biologie. III. Mceurs et réproduction de la Rossia macrosoma 
(d. Ch.). Arch. d. Zool., Expér. et Gén. (3), 2. 
