124 CASTALIA PUNCTATA. 



Gastalia fusca in having finer transverse markings. The tip is slightly dilated and has 

 obliqne stria3 with the transverse markings, and a very distinct shoulder, from which the 

 terminal process goes. In anteroposterior view the tip is somewhat fusiform with two 

 blunt points on each side of the origin of the terminal piece. The latter (Plate LXXVIII, 

 fig. 2 b) is largest and most slender in the middle of the foot, broadest in the ventral 

 series. The edge is finely serrated and the tip somewhat diminishes and terminates in a 

 curved claw with a secondary process beneath. Though the serrations diminish toward 

 the tip, yet there is no marked difference between the upper and the lower bristles as in 

 Gastalia fusca, Johnst. Some of the longer tips show a curve. The median bristles of the 

 example from St. Magnus Bay have unusually long terminal processes. 



The ventral cirrus arises nearer the body than the ventral papilla, and has a similar 

 structure to the dorsal, only it is shorter. All the cirri are pale. 



In life the ceratophore of the dorsal cirrus, which has the dark pigment-patch, is 

 richly ciliated, and the cilia are continued on the skin in the immediate neighbourhood 

 towards the intermediate dark patch. The blood-vessel internally passed up one side of 

 the ceratophore and down the other, but did not seem to enter the cirrus proper. 



Habits. — This species appears for the most part to frequent the deeper water, and 

 the finest examples are got there. It has much of the lively habits of Ophiodromus, and is 

 irritable and impetuous. When irritated, it gathers its cirri about it and swims rapidly 

 through the water. Yet with all its beauty, it, like the gaudy Amblyosyllis, clings to the 

 under surfaces of stones, and hides in crevices, so that, unless these are only its resting- 

 places, it has little field for the display of its attractions. 



Reproduction. — The fine pinkish colour of the feet is due to the presence of large ova 

 (September), which are grouped in masses at the base and extend for some distance into 

 the foot. 



It is probably this species which Garstang 1 found breeding at Plymouth in August. 



Two very distinct species have been included by Dr. Gr. Johnston in Britain on the 

 one hand, and by several Continental authors on the other, under the head of Psamathe 

 punctata, viz. the present form and P. fusca, Johnst. Neither Malmgren nor De Quatref ages 

 recognized the distinctions. The latter indeed groups them as two species under the 

 genus Psamathe, but, like CErsted and Johnston, he has not appreciated the differences. 

 The synonym Gastalia punctata, (Erst., is placed under each without allusion to the fact 

 that CErsted shows two bristle-tufts (dorsal and ventral) in each foot, whereas De 

 Quatrefages states as a generic character: " Pedes unirames." The bristles of the two 

 species, besides, are quite different. 



Amongst the figures of "Marine Insects" given by Baster is one 2 which probably 

 represents this species. 



This annelid appears to be both the Nereis punctata and N. pnstidata* of Montagu, 

 the latter being a greenish variety dredged off Torcross, Devonshire (MS. Drawings, 

 Linn. Soc, Plate LII, fig. 3). The N. fascicular ia of the same observer (MS. Drawings, 

 Plate XXXVIII, fig. 2) is closely allied, if not identical. 



1 ' Journ. M. B. A./ vol. iii, p. 225. 



2 ' Opuscula Subseciva/ Tab. iv, fig. 4. (1762.) 



3 This specific name is also given for an Eulalia in MS. Tab. 51, fig. 4. 



