70 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
is always of an opaque grayish- white tint (plate 38, fig. 136). The ovary of a lobster 
taken at the time of the hatching of the brood (plate 38, fig’. 138), or several weeks 
after it, is invariably, so far as my observation goes, of a light pea-green color, and 
possesses definite histological characteristics which will be considered in another place. 
The ovary of a female which is approaching maturity for the first time (see Nos. 22, 
26, 47, 58, 67, 74, 83, etc., table 20), on the other hand, is variable in color. It may have 
a flesh or almost salmon tint, a cream color, a dirty yellow, bright light-yellow, light 
olive-green color, or one of many intermediate tints. 
The interesting fact has already been pointed out that the percentage variation in 
the numbers of eggs produced by lobsters from 8 to 12 inches is excessively great. 
This points to the conclusion, which is confirmed by anatomical evidence, that the 
period at which lobsters reach sexual maturity is a variable one, extending over 
several years, over a period, at least, in which lobsters vary from 8 inches, or slightly 
under, to 12 inches, or slightly over, in length. 
THE FREQUENCY OF SPAWNING. 
Is the lobster an annual spawner, or, to put the question in another way, what 
percentage of mature female lobsters produce external eggs each year? These ques- 
tions, although of much importance, have generally received erroneous answers. 
In the summer of 1890 I first demonstrated, upon the ground of anatomy, that the 
lobster did not and could not breed annually, as had been commonly supposed. This 
is proved, first, by the growth of the ovarian eggs, and confirmed by the relatively small 
percentage of females with external eggs captured during the winter and spring. 
The growth of the ovarian eggs was followed from the time of hatching of the 
brood until the ova of the next generation were ripe and ready for extrusion. (See 
note, p. 152.) These results are embodied in table 20. In some notes published 
in May, 1891, 1 pointed out that three-fourths of the whole number of egg-lobsters exam- 
ined in the summer of 1890 in Vineyard Sound had extruded eggs during the latter 
part of July (see table 7). It was also shown that the eggs which are then laid are 
u carried by the female throughout the fall, winter, and spring, and are not hatched 
under natural conditions until the following summer” (92). The hatching period 
was given as extending over a period of about eight weeks, from May 15 to July 15. 
This agrees, for the most part, with the experience of recent years. 
Bumpus (30) gives correctly the periods of spawning — with the exceptions I have 
noted — of incubation, and hatching of the young. Garrnan (72), in a report upon the 
lobster to the fishery commissioner of Massachusetts, summarizes his results as follows : 
(1) The female lobster lays eggs but once in two years, the laying periods being two years apart. 
(2) The normal time of laying is when the water has reached its summer temperature, varying in 
different seasons and places, the period extending from about the middle of J une till about the 1st of 
September. 
(3) The eggs do not hatch before the summer following that in which they were laid, the time 
of hatching varying with the temperature, and the period extending from the middle of May till 
about the 1st of August. 
These conclusions — subject to the corrections which I have pointed out — are essen- 
tially a repetition and confirmation of facts which were already known. 
Mather emphasizes (135,136) the facts that the lobster carries its summer eggs all 
winter and that it breeds once in two years. 
In order to prove with certainty that the lobster can not breed every year, we 
have only to dissect a female which has recently produced a brood, or has external 
eggs nearly ready to hatch, in June, July, or August. In table 20 records of over 
