THE AMERICAN LOBSTER. 
163 
of tlie exoskeleton can be seen. The adolescent forms are all from Casco Bay region, 
and are described in table 32. (See also descriptions of figs. 9-18, plates 8-13.) The 
smallest (plate 8, fig. 10, No. 1, table 32) is a male, 1.0 inches long. The right cutting- 
claw happens to be much under the normal size, since it is in process of regeneration. 
It would probably have attained its normal size after the next molt. The greater 
breadth of the “tail” or pleon of the female is not noticeable until at a considerably 
later period. Other secondary characteristics, such as the seminal receptacle and 
first pair of pleopods in both sexes, are not fully developed until the animal has 
reached the length of about 2 inches. 
The most striking characteristic of these adolescent stages, in compai'ison with 
the adult form which they so closely resemble, is the large size of the stalked eyes 
(plates 8-12). The eye is very much compressed laterally, and in size and shape 
resembles that of Penteus. The eyes of the adult are relatively much smaller. (See 
table 38.) It is therefore possible that the large size of the eyes in the adolescent 
stages is an ancestral character. The present lobsters have probably descended 
from the Erymoid Crustacea which inhabited the seas of the Liassic period. “In the 
latter part of the Jurassic epoch,” says Huxley (103), “the Astacine type — that of the 
modern crayfishes — was already distinct from the Homarine type, though both were 
marine.” Hoploparia, which is found in a fossil condition in the Cretaceous and early 
Tertiary formations, combines the characteristics of Homarus (Astacus in this work) 
and Nethrops. I have seen nothing but fragments of this genus figured, but in the 
Eryma leptodactylina of Zittel (SOS) the eyes are relatively quite large, as we see them 
in the adolescent lobster at the present time. 
Another characteristic of these early stages is the fringe of very long setm on the 
caudal fan and the matted tufts of sette about the ends and toothed edges of the 
cutting-claw. (See figs. 13-15.) 
In a female lobster measuring 3f inches in length (No. 22, table 32) the general 
color is a dull reddish brown. The upper parts are spotted and mottled with darker 
brown ; the tips of the claws and projecting spines are generally reddish, as in the adult. 
A suffusion of light blue is seen, as in younger forms, at the joints of the appendages 
and on the edges of the carapace and abdominal terga. This coloration closely resem- 
bled that of an adult egg-bearing female which I had at the time. A small male (No. 
23, table 32) resembled this female very closely in color. The adolescent period is a 
long one, and the gradual development of the pigments of the adult is correspond- 
ingly slow. The history of the development of the color of the adult lobster from 
that of the larva will be discussed in another place. After this general account of the 
period of adolescence, I will now add all the notes which I have gathered that throw 
any light upon this important subject. In tables 32 and 33 the history of 63 imma- 
ture lobsters, varying from 1.3 to 5.6 inches, is briefly given. 
I am indebted to Mr. M. B. Spinney, of Cliffstoue, Maine, for a valuable collection 
of small lobsters from the shores of Casco Bay and Small Point Harbor, which he has 
examined with great care. This collection embraces 36 individuals, 22 of which are 
males and 14 females. They were captured mostly in October and November. Mr. 
Spinney found young lobsters from 3 £ to 4 or more inches long in considerable abun- 
dance under small stones, where at an extreme low tide there would be but 1 or 2 
inches of water; the smallest lobsters were found down among the stone piles, where 
the stones were four or five tiers deep. They crawl as far as they can into the laby- 
rinthine passages between the stones, and are here secure from every enemy. 
