248 



ENTEROPNEUSTA FROM THE SOUTH PACIFIC, 



Subgenus 2. Tauroglossus. 



2. Ptychodera carnosa n. sp. 



Colour, Measurements and External Form. 



This is a giant Enteropnenst like Pt. gigas and Pt. rohinii, the latter according 

 to Spengel being the Atlantic form of the Mediterranean Pt. clavigera'^. 



Table of Colour and Measurements (in mm.). 



Speci- 

 men 



Colour 



Proboscis 



Collar 

 length 



Branchial 

 region 



Genital region 



Inter- 

 mediate 

 tract 



Hepatic 

 region 



Abdominal 

 and caudal 

 region 



1 



Rich yellow 

 throughout, faint 

 salmon tinge in 

 genital pleurae 



6 



17-5 













2 



Pale yellow 

 throughout 



8 



16 













3 



Prevailing colour 

 of branchiogenital 

 region, dark sal- 

 mon or purplish 



10 



22-5 

 [Max. 

 width 

 behind 16] 



92 



160—170 

 [Width across 

 outspread genital 

 pleurae behind 

 pharynx 35] 



10 



106 



About 

 I foot 



4 



Genital pleurae 

 with salmon- 

 coloured gonads 



' 1 



14 



; [Width 

 1 9—10] 



26-5 

 [Width 

 10—12] 











5 



Salmon-coloured 

 gonads ; collar 

 creamy yellow, 

 darker in centre 





12-5 



29-5 



64 









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. rohinii 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. 



