674 MR J. T. CUNNINGHAM AND MR G. A. RAMAGE ON THE 



Spirorbis borealis, Morch. 



Serpula spirorbis, Linn, S. N., xii. p. 1265; Miiller, Prodr. Z. D., p. 236. 

 Spirorbis borealis, Morch, Naturb. Tidskr., 3 R. 1 B., 1863; Malmgren, 

 Annulata Polychseta ; M'Intosh, Fauna of St Andrews. 



Common on Fuci on the shore. Very common on Fucus serratus at Dun- 

 bar. We found it there breeding freely at the beginning of June. The ova 

 form a cylindrical cord, consisting of two or more linear series, and lying 

 beneath the animal in the tube, not in the operculum. The embryos were well 

 advanced in development before hatching (Pis. XLV. and XL VI. fig. 37). 



Spirorbis lucidus (Mont.), Morch. 



Serpula porrecta and spirillum, Fabr., F. Gr., p. 378. 

 Serpula spirillum, Miiller, Prodr. Z. D., p. 236. 

 Spirorbis lucidus, Morch, Malmgren and M'Intosh, loc. cit. 



Common on hydroids dredged in the Firth (PI. XLV. fig. 38). 



Fam. CHLORHJIMIDiE. 



Trophonia plumosa, Johnston, (Mull.). 



Amphitrite plumosa, Miiller, Prodr. Z. D. n. 2621, p. 216. 

 Trophonia plumosa, Johnston, Cat. Brit. Mus. ; Malmgren, Annulata 

 Polychseta ; M'Intosh, Fauna of St Andrews. 



Common in the mud among Laminarian roots, also under stones in the 

 Laminarian zone. 



The pseudhsemal system consists of a dorsal and a ventral longitudinal 

 vessel, united by a pair of lateral commissures for each somite. The posterior 

 portion of the intestine receives its blood supply by vessels passing vertically 

 upwards from the ventral longitudinal trunk. The long backward loop is 

 supplied by two trunks arising one behind the other from the ventral 

 longitudinal vessel, in about the 9th and 10th somites ; from these the fluid 

 finds its way into a series of lacunar spaces in the intestinal wall, through 

 which it passes forward to flow into a large heart placed over the oesophagus. 

 The heart is somewhat pyriform, being thicker at its posterior end, where it 

 receives the blood from the intestine, and tapering anteriorly, where it divides 

 into two trunks just behind the cerebral ganglion. These give off vessels to 

 supply the branchiae. The dorsal longitudinal vessel opens into the heart 

 about the middle of its length. 



The above account differs very much from that given by Horst (Zool. Anz., 

 viii. p. 12), who from what he saw in transverse sections of Brtida, concluded 

 that in Chlorlnemidse the only representative of a free dorsal vessel was the 



