162 CLASS IV. 
** Body armed posteriorly with zones of horny sete. Mchiwrus 
Cuv. (Zchinurus). 
Sp. Thalassema echiurus, Lumbricus echiurus Pauu., Mise. Zool. x. Tab. 1, 
fig. 1—8, ForBers, Brit. Starf. p. 263, Guir. Iconogr. Zooph. Pl. 6, fig. 3 ; 
on the coasts of the North Sea ; this species is used by the fishermen for 
bait ; it is flesh-coloured, here and there translucent blue and red; the 
spines are shining and yellow, as far as they project from the body. The 
orange-coloured intestinal canal is long, with many undulations and 
vesicular expansions. There are two long, brown, somewhat tortuous, 
cecal tubes near the anus, and four white vesicles at the anterior part 
of the body, which belong to the procreative apparatus. The nervous 
system consists of a thread running along the intestinal cavity. The skin 
has much muscularity, so that when wounded it spirts out the contained 
water like a fountain, and then the intestines are forced out. 
*** Body furnished anteriorly and posteriorly with zones of 
setee ; with belly in the middle plane and in front of the anus 
scutate. (Sete at the sides of the scute; anal tubule conical, 
retractile.) Sternaspis OTTo. 
Sp. Thalassema scutatus RANZANI, Sternaspis thalassemoides Otto, Nov. 
Act. Acad. Leop. Carol. Tom. x. Tab. 50, GuéRIN Iconogr. Zooph. Pl. 6, 
fig. 4, from the Adriatic. Orro took the conical extremity incorrectly for 
the mouth ; see the communication relative to the structure of this animal 
by Kroun in MuELuER’s Archiv. 1842, s. 426. RANnzAnt, who described it 
before Orro, rightly distinguished the two extremities of the body, and also 
figured the spoon-shaped proboscis, in which it resembles Echiwrus. Opuscolt 
scientifice 1. Bologna, 1817, 4to. pp. 112—116, Tab. Iv. f. 10, rr. 
