Pope (1910 11) records the size of the drill egg case in the Woods Hole 

 area as averaging 7 mm long, 4.5 mm. wide, 1 mm thick, with an operculum 

 1 mm. in diameter. Stauber (1943) observed that as drills grow larger they lay 

 bigger egg cases. For example in Delaware Bay, New Jersey, a drill 16.5 mm. 

 in height deposited egg cases averaging 3.8 mm. in length, and a 29.6 mm. drill, 

 egg cases 8 .4 mm . long. Drills under 20 mm . in height rarely deposit egg cases 

 over 6 mm. long and those over 25 mm. seldom lay cases smaller than 6 mm. 



The number of egg cases produced by Uro salpinx in a number of different 

 regions within its geographic range is reported in Table 3 . Egg production is 

 not necessarily uniform over a period of years, as Stauber (1943) observed that 

 the average number of egg cases oviposited by caged drills in Delaware Bay in 

 1941 was considerably lower than that in 1940. A single female does not always 

 deposit all her egg cases at one time, but may lay a number of clutches during 

 the breeding season ( T. C. Nelson, 1922; Engle, 1940; Cole, 1942); and the number 

 of egg cases laid in a cluster at one time is quite variable . Pope (1910 11) noted 

 that egg laying will often extend for a period of several days, and he found a 

 minimum of four and a maximum of 150 egg cases in clusters . A number of 

 females may oviposit together and this probably accounts for Pope's maximal 

 figure . In detached clusters laid by isolated females the range in the number of 

 egg cases varied from 4 to 22. Cole (1942) observed that capsules are deposited 

 at the rate of 3 or 4 per day. 



The data tabulated in Table 3js not entirely comparable. T. C. Nelson 

 (1922) observed oviposition for only about a month, which probably did not include 

 the total egg laying period; Galtsoff (Galtsoff et al„, 1937), according to Stauber 

 (pers. com.) began his observations in 1935 after oviposition had started and 

 terminated them in June, 1936, before oviposition had ceased; and Adams (1947) 

 has recoided only a limited quantity of data. A possible source of error is in- 

 troduced by the lack of information on the relation of the number of egg cases 

 deposited per season to the age of the drill, although it is likely that up to a 

 point the rate of oviposition may accelerate with age. A serious source of 

 error in all these estimates of oviposition is found in the lack of information on 

 the proportion of drills under observation which were females . Further, it has 

 not yet been demonstrated by controlled experiments that confining drills in cages 

 does not alter total seasonal oviposition. At best these preliminary data tenta- 

 tively indicate that Urosalpinx deposits an average of approximately 45 egg cases 

 per season a starting with a minimum of zero in immature females and reaching 

 a possible maximum of 96 cases per season in older mature females 



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