424 DR W. CARMICHAEL M'INTOSH ON THE STRUCTURE OF THE 



of the enlarged base. This animal is quite different from the T. maculata of Sir 

 J. Dalyell, which may be a species having a speckled aspect in spirit, a single 

 pair of branchiae, and hooks of the form shown in Plate XIV. fig. 15. The 

 Grymcea bairdi, Mgrn., a form nearly allied to Thelepus circinnatus, Fabr. 

 ( Venusia punctata, JohnstO, was dredged in 90 fathoms off St Magnus Bay, 

 Shetland, by Mr Jeffreys. It is at once distinguished from the latter by the 

 much greater prominence of the bristle-papillae, and the greater length and lustre 

 of the bristles themselves throughout the entire body. The hooks resemble those 

 of the common species (T. circinnatus) very much, but the process for the liga- 

 ment is not so near the tip of the upper curve as in the latter, and the organs are 

 proportionally smaller. The tube is composed of fine grains of muddy sand, in- 

 stead of the coarser and stronger structure of T. circinnatus. 



Amongst the Polycirridea from the same region is a very interesting form, 

 called by Dr Malmgren Lysilla loveni, and distinguished by the largely dilated 

 cephalic lobe, furnished with numerous clavated grooved tentacles along its 

 margin, and a cluster of tangled filiform processes interiorly at each side. The 

 whole of the anterior dorsal region is densely tuberculated with papillae, which, 

 from the intervening lines, assume a transverse arrangement. On the ventral 

 surface, which is thrown in contraction into two prominent longitudinal folds with 

 a central depression, the swollen portions are covered with somewhat larger 

 tubercles than the dorsum, but the depressed central region forms a nearly 

 smooth line of demarcation. There are six pairs of foot-papillae in front, each 

 having a short tuft of simple slender bristles, whose tips in the preparation are 

 entirely within the summit. From the same source as the latter there is also the 

 anterior fragment of another curious and new example of the same sub-family, 

 J Poly cirrus tribullata, n. s., which has neither bristles nor hooks. The head and 

 tip have the usual tentacles. The body has no ventral plates, but only a raised 

 central line. There are three pairs of well-marked circular truncated papilhr 

 (on the sixth, seventh, and eighth segments), each consisting of a raised ring 

 externally, with an elevation in the centre. Two minute papillae were visible in 

 front of the first flattened process, but only a trace of an elevation occurred on 

 the lateral region of the succeeding segments, which were two-ringed. The 

 cuticle has a minutely granular aspect. The remarkable lateral processes may 

 act as suckers. Two species, which come under Dr Malmgren's recently con- 

 stituted genus Ereutho, are not uncommon in Britain. They are distinguished 

 from other Polycirridea by having thirteen pairs of bristle-bundles. The first, 

 which seems closely allied to E. smitti, Mgrn., has hooks (Plate XV. fig. 17), 

 which possess only two fangs, and a very much produced and characteristically 

 striated basal process. The hooks of the other species (Plate XV. figs. 18 and ]9) 

 are much smaller than the foregoing, and so exactly resemble the figure by 

 Malmgren from a specimen of P. aurantiacus, Grube — forwarded by Prof. Grube 



