292 SIDNEY F. HARMER. 



Median process with greatly deve- 

 loped lateral wings^ wliicli 

 unite with the sides of the 

 zooecium 5. S. connexa. 



Median process simple, without 



lateral wings . . . .4. S. simplex. 



^< 



An asymmetrical tube, without late- 

 ral wings, springs from the 

 descending cryptocyst . . 1. S. lateralis. 

 ' A median process bounded by late- 

 ral wind's is differentiated on 

 the upper surface of the tube . 11 



f Median process with a longitudinal 



I groove 2. S. sulcata. 



1 1 <^ The roof of a well-developed tube 



forms the convex floor of the 



median process . . . 3. S. tubulosa. 



The determination of the species will be facilitated by 

 noticing that in S. maguilabris, S. neozelanica, S. 

 tubulosa, S, sulcata, and S. lateralis the ci-yptocyst 

 joins the basal wall at a distance from the distal wall, leaving 

 a considerable amount of the basal wall exposed from above; 

 that in S. Buskii, S. Haddoni, and S. truncata the 

 cryptocyst joins the distal wall, the opening of the tube being 

 clearly visible from above, but not the basal wall ; and that 

 in S. auriculata, S. connexa, S. simplex, and S. al- 

 veolata the cryptocyst is inserted at or near the junction 

 of the basal and distal walls, the opening of the tube not 

 being visible from above except in some zooeciaof S. alveo- 

 lata, which is sufficiently distinguished in other ways by its 

 quadrilateral zooecia and by the alveoli which receive the 

 points of the teetb, in the b zooecia. 



