NOTES OX THE FREE-LIVING NEMATODES. 471 



E-habditis from the neighbourhood of Cambridge which I 

 cannot adequately describe from the notes taken at the time 

 It was remarkable for the very small proportion of fertilised 

 eggs laid by each individual. In one family six hermaphro- 

 dites were selected before maturity, and their fertility com- 

 pared. In eacli case the separate numbers represent the 

 eggs laid in a day, and those in brackets tlie total of fertile 

 eggs: 



A 1, S, 1, 1, 7= [24] B 9, 10, 4, 4=: [27] C 9, 9, 3, 2= [22] 

 D 7,4, 12, 8, 2 = [33] E 9, 7, 7, 5, 3= [31] F 7, 6, 1,1= [15] 

 These cultures were carried on in July. Others, began 

 later in August, gave rather higher numbers, e.g. : 



A 1, 7, 13 (and 2 unfertilised eggs), 12, 1=[34] 



B 14, 3, 8, 6, 5 =[36] 



C 15, 17, 11= [43] 



D 8, 10, 8, 5, 2= [33] 

 In A of this second series it will be noticed that the succes- 

 sion of fertilised eggs was interrupted temporarily, but 

 whether this was due to a retarded production of spermatozoa, 

 as in Rhabditis gurneyi, or to some other cause, was not 

 discovered. It is much to be regretted that no trustworthy 

 observations on the occurrence of males were made, for a 

 species like this in which the hermaphroditism is of such an 

 apparently recent and inefficient type, should, according to 

 Maupas' conclusions, possess a very large proportion of 

 males, which was not, however, observed. It is hoped that 

 the species may be rediscovered and this point investigated 

 again. 



Rhabditis coronata Cobb, which Avas investigated by 

 Maupas (pp. 537-541) and shown to be a protandrous herma- 

 phrodite, is probably a similar form with very low fertility. 

 No figures are given of the total of eggs laid, but it is 

 mentioned that an isolated hermaphrodite only laid six eggs 

 in twenty-four hours, and that in general eggs were laid very 

 slowly. An interesting feature shown in Maupas' drawing 

 of the species (PI. XXI, fig. 8) is the small size of the ovarian 

 part of the gland, which might well account for a restricted 



