THE ENTEROPNEUSTA. 635 
The vermiform process is usually well-marked and coextensive with the dorso-ventral 
muscles. In the instance where these muscles were reduced the vermiform process had 
altogether disappeared. 
Collar. Willey states that “there is no dorsal septum in the collar, except the fold 
of basement-membrane associated with the first vestigial root, which is probably to be 
regarded as a vestige of the dorsal septum. On the other hand the ventral septum has 
an unusual forward extension, commencing a short distance behind the region of bifurcation 
of the nuchal skeleton.” In the Maldive forms the dorsal septum is present though only 
at the hind end of the collar (Text-fig. 120, ds.), whilst no ventral septum is to be found. 
A vestigial root was found in one of the three specimens examined. It was, however, 
very small and did not reach to the epidermis (Text-fig. 120, r.). Both anterior and posterior 
neuropores are very deep, so that only about 4 of the collar cord is devoid of a continuous 
lumen. This portion contained traces of a cavity. 
In his specimen Willey found that the cornua of the nuchal skeleton extended to the 
extreme posterior end of the collar. This may be the condition in the Maldive specimens, 
whilst on the other hand the hindermost quarter of the collar may be without cornua. 
The collar canals open into the first branchial pouch and I have been unable to find 
the truncal canals described by Willey. 
Trunk. The branchial and genital regions agree closely with Willey’s account. 
In the hepatic region there is no internal circular musculature. The longitudinal muscles 
are gathered into three bands on either side, viz. a dorsal, a ventral, and a lateral one 
(Pl. XLI. fig. 5). Consequently there are in this region two longitudinal areas where no 
muscle fibres intervene between the intestinal wall and the epidermis. 
In the intestinal. region there is a longitudinal dorsal groove on either side which 
shews slight depressions at intervals (Pl. XLI. fig. 7). The circular muscles form a complete 
ring round the body here but the longitudinal muscles are wanting beneath the grooves. 
The intestine itself is small and laterally compressed, the body cavity being occupied by 
strands of connective tissue. 
Although there are several small points of difference between the Maldivan forms and 
Willey’s specimen I have thought it best, in view of the considerable variations shewn on 
these very points, not to separate these forms from Willey’s. It is possible that when more 
material is forthcoming the differences may be found to be sufficient to separate them as 
distinct varieties. 
Spengelia maldivensis, n. sp. (Pl. XLI. figs. 6, 8; Pl. XLII. fig. 20). 
Locatiry, ETC. Hulule. From beach sand-rock. A single specimen only was obtained 
and this lacked the posterior part of the body, which was broken away in the genital region. 
EXTERNAL FEATURES. A small form and the colour after preservation is quite white. 
The total length of the fragment obtained was 21mm. Of this the proboscis measured 
4mm., the collar 1‘8mm. (with a width of 3mm.), whilst the length of the branchial region 
was 6mm. Characteristic is the shortness of the collar, the length of which is not much 
more than half its width. The width of the genital region did not exceed 3 mm. 
