2l6 BUMPUS. [Vol. V. 



they have a length of but 20 cm., and when, I have every reason 

 to suppose, they cannot deposit eggs until a year if not two 

 years later. 



Though the modified abdominal appendages of the male 

 lobster have often been described, and the spermatophores of 

 Decapods were discovered by Kolliker, and again described by 

 Grobben (78), the receptive apparatus of the female has, I be- 

 lieve, thus far escaped detection. This organ lies at the poste- 

 rior end of the sternum of the female lobster, resting between 

 the bases of the IV and V pairs of thoracic appendages. It 

 is a highly colored, heart-shaped body, represented on PI. XVIII, 

 Fig. 1. On the same plate, Fig. 2, a side view is given. The 

 openings of the oviducts (ov. or.) lie anteriorly, while a keel-like 

 piece (K) stands as a wedge between the laterally and poste- 

 riorly directed wings ( IV). If the wings are forcibly depressed, 

 a whitish substance is seen to ooze from between them and the 

 keel at Sp Or. of Figs. 1 and 2. The microscope proves this 

 to be the spermatic fluid. Reference to Fig. 2, which represents 

 a longitudinal section through this region, will reveal the pres- 

 ence of a capsule lying inside the wings of the receptive appara- 

 tus and indicated by Sp C. It is mostly filled with a gelatinous 

 cement-like substance which is quite transparent. Posteriorly, 

 however, a whitish portion {Sp P.) made up of male cells, — is 

 more fluid, and may leave the capsule through the openings 

 already referred to. Until the male lobster has been actually 

 observed in the act of charging this capsule, there will be some 

 question as to the way in which he manoeuvres. Actual copula- 

 tion, however, has been observed in the cray-fish, and the struc- 

 ture of the first abdominal appendages of the male lobster are 

 so nicely adapted to opening the receptive orifices of the female, 

 that there seems little reason for doubting that the ventral sur- 

 faces are applied to each other during copulation. 



The spermatophores of the male may be artificially pressed 

 from the vasa deferetitia, and if floated in sea-water assume a 

 characteristic shape. Gruber ('79) has shown that the spermato- 

 phores of Copepods become much more concentrated when 

 finally within the receptive capsules of the female, and the same 

 is true of Homarus. 



Contrary to the inductions made by Paul Mayer in his valu- 

 able paper on the development of Eitpagurus (77), it seems to 



