332 GEOLOGICAL SURVEY OF THE TERRITORIES. 
wide as two-thirds its length. The outer angle or elbow varies greatly, 
in some individuals not being noticeably produced, and with the outer 
edge nearly straight, while in others the angle is remarkably produced 
and the outer edge is much excavated. In one specimen, 7™™ in length, 
the claspers are one-half as wide as in another, but with the elbow still 
produced. In another male, 7™™ in length, selected from fifty more or 
less normal individuals, the elbow is enormously produced, and the 
claspers are small, long, narrow, and acute. In sixty other males the 
elbow is a good deal produced, while the claspers are broad and triangu- 
lar. These specimens were collected at Lake Point from the wharf, July 
26, 1875, the temperature of the water under the wharf in the shade 
being 73° F. The females bore about 23-24 eggs in their ovisaes. 
Sixty red-colored males from a hot, shallow “brine pool at Farming- 
ton, late in July, the temperature of the water probably not less than 
80° Fahr., were examined. Of these, one male, 5.5™" in length, had 
claspers which were even smaller and narrower than in a smaller indi- 
vidual, 4.5°" in length, showing an unequal degree of growth, being 
perhaps an example of retarded development of a secondary sexual 
character. A stronger example is seen in two individuals of the same 
length (5.5); one was very immature, the head being smaller than in 
the other, the claspers unusually small and narrow, the genital append- 
ages smaller, and the caudal appendages one- half as ‘long as in the 
other; in the second example the head is large and the claspers fully 
three times as broad as those of the first individual, being three quar- 
ters as broad as the space between the eyes, while the caudal append- 
ages were twice as long as thick, longer than those of A. gracilis, as 
fioured by Veryrill. This difference i in two specimens so nearly of a size 
shows that the sexual characters are suddenly acquired. No young 
were observed less than 3™ long. 
Identity of A. fertilis, A. gracilis, and A. monica.—On compa ing 30 
males of A. gracilis from New Haven the claspers in small specimens look 
like Verrill’s figure of those of A. gracilis ; in large specimens like that 
of his figure of A. monica, the claspers increase in width with age. In 
two specimens of the same size and probably age, one has very narrow 
claspers, aS in Verrill’s figure of gracilis, in another the ciaspers are 
_ broader than in his figure of A. fertilis. In half-grown males the claspers 
are narrow, as in Verrill’s figure of A. gracilis. The forms of the caudal 
appendages vary with age. 
On comparing a few days after, to be sure that I had made no mis- 
take, 200 males of A. fertilis with males of A. gracilis, I could find abso- 
lutely no essential specific or varietal differences between these so-called 
species. 
On examining 45 females of A. gracilis from New Haven, and com- 
paring them with a number of Salt Lake females, no differences could 
be observed. Comparing with care a large female from Utah (Great 
Salt Lake) with one from New Haven of the same size, there was also 
the same proportion of parts. The eyes were ot the same size, the eye 
stalks of the same length; the first and second, the latter especially, 
had the same proportion. The feet and endites were the same, and 
the length of abdomen the same, though this region varies, as it 
irregularly contracts in alcohol. The egg-sacs in the New Haven ex- 
ample are a little longer and with a more acute lateral angle than in 
Utah examples, but this depends on age, and these differences disappear 
‘In those which are of the same size and degree of sexual maturity, and 
in which the eggs are similarly developed. The caudal appendages in 
the Salt Lake example (which was 12.5"" in length) are nearly but 
