268 C. L. TURNER. 



The specimen collected by Williamson was one of Cambarus 

 rnsticus. The first abdominal appendages were not fully devel- 

 oped but were clearly of the male type while all the other second- 

 ary sexual characters were of the female type. 



DESCRIPTION OF NEW CASES. 



Specimens I, 2, j, 4 and 5. (Fig. 5.) These five specimens are 

 identical in their peculiarities and it will therefore suffice to 

 describe one of them and to give the lengths of the other four. 

 The length of the specimen described is 48 mm. The lengths of 

 the others are 45, 47, 49 and 52 mm. respectively. In the speci- 

 men 48 mm. long the secondary sexual characters are typically fe- 

 male but there are the following additional characters : copulatory 

 hooks are present at the base of the third walking legs; the first 

 abdominal appendages are modified to resemble somewhat those 

 of the male of the first form, being shorter, however, (8 mm. in 

 length) with the tips undivided and curved toward the median 

 line (Fig. 10); the second abdominal appendages are those of a 

 normal male (Fig. 10). A dissection of the internal organs has 

 been made and ovaries and oviducts have been found. The eggs 

 are full sized and would normally have been laid within two 

 months. The ovaries are heavily parasitized by the embryos of 

 a flatworm l to such an extent that many of the eggs are entirely 

 replaced by the encysted embryos. No trace of a testis or of a 

 vas deferens is present. 



Specimen number 6 is 42 mm. long. It differs from numbers 

 i, 2, 3, 4, and 5 only in the degree of development of the first 

 abdominal appendages. The right member of the pair is in all 

 respects like the homologous appendage of the normal male of the 

 second form. The left member of the pair is slightly shorter and 

 the tip is bent toward the median line. 



Specimen number 7 is 54 mm. in length and is typically female 

 in all its secondary sexual characters except in the case of the two 

 abdominal appendages. The first abdominal appendages are 

 modified like those of cases I, 2, 3, 4 and 5 and are of the same 

 size. The second abdominal, appendages differ only slightly 

 from those of the female, being a little stronger and the iniu-r 



1 The writer is indebted to Professor A. S. Pear -< i iln I nivcrsity nt" \Vi-.-c m-on 

 for identifying the parasites as Microphallus opacits Ward. 



