412 



I\Ir. II. A. Baylis on 



stronp:ly coiled tail, atul are provided with two spicules, 

 which, thoTi^h small, are easily seen in cleared specimens. 

 These spicules (fi^s. 1 and 2 B) are unequal in length, 

 measuring 0*G2 mm. (left) and 0*3 mm. (right) respectively. 

 They are completely covered externally with small rough 

 granulations. Each spicule is considerably expanded at its 

 proximal end and blunt distally. 



The. tails of both sexes show a very marked difference in 

 size betweeji the * Terra Nova ' and ^Ir. Bennett's specimens. 



In the male (fig. 2) the distance from the cloacal ajjcrture 



Fig. 1. 



Crassicaudn crassicauda. The two spicules of the ninle, seen from the 



left side. 



to the tip of the tail is about three times as great in tlie 

 former as in the latter. In the female (tigs. 3 and 4), in all 

 cases and in both species, tlie rurions constriction in tlie region 

 of the vulva, described and figured by Creplin, is well-marked. 

 The vulva (ligs. 3 A and 4, v.) lies towards the anterior end 

 of the constriction, and the caudal end assumes theshaj}eofa 

 rounded or oval knob. Tlie anus (figs. 3 A and 4, a.) lies 

 in a de|)ression at the posterior end of the latter. According 

 to Cre])lin's figures, the terminal knob would measure 5 mm. 

 in length in an exceptionally large specimen. Leiper and 



