80 



J. A. ALLEN, H.L. SANDERS AND F. HANNAH 



6CH 



W -fcfcjf 



40-1 



80 



70 



h\l- '**&*<:* 



Fig. 130 Portlandia 

 minuta. Lateral views of 

 shells from the left and 

 right sides, detail of the 

 hinge-plate of a left valve 

 and the dorsal view of a 

 shell. Specimens from Sta. 

 203, Cape Basin. (Scale = | 

 1.0 mm). 



Thereafter it makes a single loop to the right side of the body. 

 A small amount of food material was observed in parts of the 

 left digestive diverticulum. The kidneys are small. Gonads 

 are present in specimens larger than 1.6 mm. The testes occur 

 dorsally, ventrally and internally to the digestive diverticula; 

 with posterior dorsal and lateral extensions. 



In the course of growth, the valves become more inflated 

 and more rostrate but there is little change in the height/ 

 length or posterior umbonal length/ total length ratios (Fig.| 

 131). Hydroids were present on one individual and these! 

 covered the dorsal and posterior shell margins. 



60- 



40 



PL\TL 





Length (mm) 



Fig. 131 Portlandia fora. Variation in ratios of height H/L, width 

 W/L and postero-umbonal length PT/TL to length against length 

 of a subsample taken from Sta. 203, Cape Basin. 



byssal gland in the heel with a relatively large blood space 

 surrounding it. The nervous system is well-developed with 

 large 'club'-shaped visceral and cerebral ganglia and large, 

 round, pedal ganglia with associated large statocysts dorsal to 

 them. The stomach and style sac are large. From the style sac 

 the hind gut penetrates the foot for a short distance before 

 turning dorsally to parallel the posterior edge of the body. 



Fig. 132 Portlandia fora. Lateral view from the right side of the 

 internal morphology of a specimen from Sta. 203, Cape Basin. 

 (Scale = 1.0 mm). For identification of parts see Fig. 34. 



