248 



ENTEROPNEUSTA FROM THE SOUTH PACIFIC, 



Subgenus 2. Tauroglossus. 



2. Ptychodera carnosa n. sp. 



Colour, Measurements and External Form. 



This is a giant Enteropuenst like Pt. gigas and Pt. robinii, the latter according 

 to Spengel being the Atlantic form of the Mediterranean Pt. clavigera 1 . 



Table of Colour and Measurements (in mm.). 



The immature eggs are purple and are surrounded by orange-coloured fat-globules, 

 the combination of the two colours producing the salmon tone. As the eggs ripen 

 the pronounced purple coloration is lost and the fatty matter seems also largely to 

 lose its colour, so that the result is a dull neutral tint. Sometimes the prevailing 

 colour of the genital pleurae is dark with a violet tone. 



The posterior zone of the collar is sharply differentiated from the other zones. 

 In paler specimens it is intensely white, while in the more richly coloured individuals 

 it is not so conspicuous but always to be recognized. 



1 If Spengel is right in regarding Pt. robinii as a giant variety of Pt. clavigera, it furnishes an interest- 

 ing analogy with the large Amphioxus (8 cm. long) of the coasts of France as compared with the smaller 

 Mediterranean form. 



