PLATE XIII 



Fig. i. A left-handed specimen from Lanzarote, no. 25. Ventral tract 

 seen from inside the float (above), oral end to the right after in- 

 jection of black gelatine into cormidia (except I), x 13. 



Fig. 2. A young left-handed specimen from Lanzarote, no. Juv. B, 

 float-length 8 cm., seen from above or windward side. The dis- 

 tinctness of the groups of cormidium I can be seen at the aboral 

 end (left). The largest ampulla is that of group 2 of cormidium II. 

 Parts of cormidium I and II are obscured by the black back- 

 ground inserted under the groups of cormidium I. The other side 

 is shown in fig. 4. x 2. 



Fig. 3. The same specimen. Cormidium II from the windward side. 

 At top left (aboral end) appears the precocious gastrozooid of 

 group 1, and below its point of attachment is the slender peduncle 

 of its gonodendron. Its (main) tentacle and ampulla lie to the right. 



x 5-7- 



Fig. 4. The same specimen. Cormidium I seen from below or the lee- 

 ward side. The other side is shown in fig. 2. The tentacle of group 1 

 is on the left, x 5. 



Fig. 5. The same specimen. Cormidia III, IV, V and VI. Main 

 tentacle of II on the left. Note the four prominent gastrozooids of 

 the first groups (which do not bear tentacles) that grow directly 

 from the bladder-wall, and are some of the earliest buds to appear. 

 The large horizontal gastrozooid is part of group 1 of cormidium 

 III. The vertical two gastrozooids at a lower level are parts of 

 groups 1 of cormidia IV and V. The horizontal gastrozooid at a 

 higher level (right) is part of group 1 of cormidium VI. x 5.7. 



Fig. 6. The same specimen. Cormidium III seen from the windward 

 side (oral end to the right). Gastrozooid and gonodendron of 

 group 1 on the right. Terminal lateral groups on the left. This 

 stage of development is rather later than that shown in the figures 

 of specimen K2. x 5-7. 



