NEW ECHIUROID AND SIPUNCULOID WORMS—FISHER 353 
The ecology of 7. philostracum is different from that of 7. thalas- 
sema, which Lankester describes as living (on the south coast of Devon- 
shire) in galleries excavated in the red sandstone by the lamellibranch 
Gastrochaena. ‘There is probably some difference in the dimensions of 
the fore-gut, that of philostracum being slightly longer. Judged by 
Rietsch’s figures (1886, pl. 21, figs. 96, 99) the nephrostome of thalas- 
sema is much smaller. His figures of specimens taken at Concarneau 
indicate that the margin of the proboscis very definitely forms the 
lower lip (figs. 92, 93), but Jameson (1899, p. 545) states: ‘The mouth 
lies at the base of the proboscis, the lateral margins of which meet but 
do not fuse ventrally. That is to say the under lip belongs to the body 
and not to the proboscis.” The structure of the cloaca appears to 
differ as mentioned in the description. 
There is no indication in alcoholic specimens of a division of the body 
into three regions, as is said to be characteristic of thalassema (Leigh- 
Sharpe, 1928, p. 499). 
THALASSEMA HARTMANI, new species 
PuatE 9 
Diagnosis.—Nephridia 2; nephrostome pedunculate, inconspicuous, 
without trace of spirals; dorsal blood vessel posteriorly voluminous, 
encroaching upon intestine, the ring vessel being distal to junction of 
fore-gut with intestine; segment of intestine between end of fore-gut 
and beginning of siphon exceedingly long, equaling or exceeding length 
of extended specimen; skin papillae numerous, elongate, unequal, not 
obviously in serial arrangement or larger at ends of body; setae with 
interbasal muscle, the hook not sharply bent; lower lip of mouth formed 
by flange of proboscis. Type: Length 40 mm; proboscis, 8 mm. 
Deseription.—Body wall thin in expanded specimen, slightly trans- 
lucent; papillae prominent, unequal in size, the larger being swollen 
squamiform and bent anteriorward; no evident serial alinement; setae 
3.5 mm., with broadly curved flattened, tapering ends; proboscis fleshy, 
forming thick under lip to mouth; no localized thickenings of longitu- 
dinal muscle layer; inner layer very thin, with satiny luster. 
The single pair of nephridia are small in the type; the nephrostome 
is simple and represents only the slightly expanded end of its rather 
long peduncle, which springs from the base (anterior side) of the neph- 
ridium. The anal vesicles are relatively very small with tiny ciliated 
funnels. 
A characteristic feature of this species is the extremely long segment 
of the intestine that precedes the siphon—far longer than in any known 
species of Thalassema, s.s. It is not possible to measure this accu- 
rately, but it is of the order of five times the length of fore-gut. The 
fore-gut seems to lack a stomach, or crop, behind the gizzard. The 
