NATURAL HISTORY OF AMERICAN LOBSTER. 319 
strengthened with yellowish deposits of chitin of a horny consistency. (Fig. 3, pi. 
xliv, bar.) 
The stylets or modified appendages of the first abdominal somite in the male (fig. 
1, a, pi. xxxix and fig. 5, pi. xliii) have stout stalks and a single terminal blade. The 
latter is nibbled at the end, grooved along the median side, and bent in such a manner that 
when the stylets are opposed they form a covered way. At their hinder extremity they 
leave a wide open angle, but partially closed by the spurs of the second pair of swim- 
merets (fig. 2, a, pi. xxxix, sp.) when these appendages are naturally extended forward 
On the anterior or upper side of the opposed stylets a deep groove on the stalk of each 
leads obliquely into the arched passageway. The tips of the stylets when held in this 
position diverge slightly, and when pressed into the seminal receptacle the elastic lips 
of the latter catch on the nibs and hold the appendages until they are forcibly with- 
drawn. The indurated tip of each stylet is interrupted by a minute oval area of soft 
membrane, but this does not appear to be the outlet of any peculiar organs. The 
tissues of the stylet itself, like those of the swimmerets, generally abound in tegu- 
mental glands and large glycogenic cells. In copulation the animals undoubtedly lie 
with ventral surfaces together, but apparently do not remain in this position long. 
After seizure of the female, the spermatophores are emitted and possibly with the aid 
of other appendages are conducted to the passage formed by the stylets, the tips of 
which are inserted nearly vertically into the spermatic receptacle and there held in the 
manner indicated. The spermatophores not only swell and soften in water, but possibly 
may be disorganized before the sperm are free to enter the receptacle, but this is not 
probable. 
The crustacean sperm, as we have seen, is like a submarine torpedo, loaded and 
primed, capable of piercing the membrane and forcing a passage into the egg the moment 
its latent energy is set free. 
While much of the preceding account is based solely upon inference derived from 
a study of the organs and of the changes which some of them are known to undergo, its 
presentation may be worth while, if only to call attention to the wide gaps still remain- 
ing in our knowledge of the whole process of fecundation in the higher Crustacea. 
