CHAP, v.] 



THE GULF-STREAM. 



369 



forms which we have since found in the Southern Sea. The 

 test is 30 mm. in length and 20 mm. in height, and very elegant 

 and symmetrical in form ; the outline is oval, slightly truncated 

 posteriorly ; a longitudinal ridge from which the sides of the 

 shell slope off with a pleasing curve runs along the apical sur- 

 face. The oral surface is nearly flat, and a slight keel runs 

 round its edge, defining and limiting it very much, as in Anmi- 

 chytes', a fasciole follows the keel, only leaving it and appear- 

 ing for a little part of its course on the oral surface in advance 



Fig. 102.— Calijvme rdicta, W'vville Tuomson. A, oral ; B, apical aspect, sli^'litly enlarged. 



(No. 54.) 



of the mouth. The mouth is oval ; its long axis in the direc- 

 tion of the antero - posterior axis of the test. The excretory 

 opening is on the posterior surface above the line of the pe- 

 ripheral ridge. The apical area is, if not disjunct, greatly pro- 

 duced ; but it is difficult to make out the exact relations of 

 some of the terminal plates of the ambulacral and inter-ambu- 

 lacral series. The ambulacra of the trivium meet at an anterior 

 pole on the dorsal surface nearly opposite the mouth, and the 

 two ovarial plates closing the two anterior inter-ambulacral se- 

 ries bear large ovarial openings from which, as in Aerobe, tubes 



