THE ENTEROPNEUSTA. 651 
with the ventral portion (Pl. XLIV. fig. 38), but the length of the branchial region compared 
with that of the collar is exceedingly short. In none of the specimens is it more than a 
quarter as long again as the collar, whilst in two cases it is even shorter than the latter 
structure. 
The post-branchial groove however is well-developed, being on the average about one-third 
of the length of the branchial region. 
The number of synapticula is very variable. As many as nine or as few as three may 
be present. 
The genital folds are large (Pl. XLIV. figs. 38, 39) in the branchial region and also 
in the region of the post-branchial groove (Pl. XLIV. fig. 41). Just behind this region 
they rapidly diminish in size (Pl. XLIV. fig. 40). In all four specimens the gonads are 
quite immature. Points of interest in connection with them are dealt with later (p. 661). 
An account of the pygochord is given on p, 659. 
Ptychodera flava, var. gracilis (Pl. XX XVII. fig. 5; Pl. XX XVIII. figs. 10,19; Pl. XLV. 
figs. 42, 44; Pl. XLVI. figs. 50, 53—55). 
Locatity, ETc. Hulule, Maldive Is. From boulder zone under stones in sand. Also 
from sand at Minikoi in company with Pt. flava, var. laccadivensis. 
With reference to the specimens from Hulule Mr Stanley Gardiner has made the 
following note:—“They are found sparingly under the stones of the boulder zone in the 
sand. A couple of specimens or more can almost invariably be obtained wherever a large 
grey Actinian lives, the latter seeming to protect the Enteropneusts. Polychaets, Sipunculids, 
and Holothurians are not generally found in the same patch of sand.” 
EXTERNAL FEATURES. This is a small variety, the longest specimen of which measured 
68 mm. after preservation, the shortest 32mm. (see Table 12, p. 673). It is somewhat slenderly 
built though the total length in comparison with that of the collar averages 196. The 
posterior portion of the animal’s body is usually very slender (ef. Pl. XXXVII. fig. 5) though 
this is not so much the case in larger specimens. The liver saccules shew an anterior dark 
group and a more extensive posterior lighter group. The saccules are not large (Pl. XXXIX. 
fig. 19) and are as a rule not at all or but slightly lobulated except in the case of large 
specimens (Pl. XXXIX. fig. 10, *). In the specimen from which the coloured sketch 
(Pl. XXXVII. fig. 5) was made all the liver saccules appear dark. It is possible that it 
is only after preservation that the darker anterior group can be separated from the rest. 
INTERNAL STRUCTURE. 
Proboscis. The musculature is rather feebly developed, the longitudinal fibres being 
gathered into widely separated radial bundles as in laccadivensis (cf. Pl. XXXIX. fig. 25). 
The dorsal muscular decussation may be feebly developed or fairly strong. Dorso-ventral 
proboscis muscles are present anterior to the pericardium. The ventral proboscis septum is 
well-developed, reaching almost to the tip of the stomochord. Of the paired proboscis pores 
only one is functional, placing the dorsal coelom in communication with the exterior. This 
may be either on the right or left side. The other pore is generally smaller and in one 
case had disappeared altogether. The racemose organ is well-marked though unlobulated or 
only faintly so. 
