of the Fishery Boctrel for Scotland. 



285 



certainly be sufficient to colour the muscles of marine fishes which feed 

 on them, if coloured they could be by such food. 



Throughout the month Appendiculariaewere seldom absent from the mid- 

 water and bottom-nets, but they did not appear in the surface-nets till 

 after the middle. As a rule they were small, and few in number, the 

 only exception being the last day of the month, when many (also small) 

 occurred in the bottom-net. July is therefore not a period when the 

 Appendicularians are in full development. On the other hand, the 

 larvae of the sedentary Ascidians are very abundant in July. 



In almost every bottom-net Cyplwnautes (like compressus) occurred — 

 more sparingly in the earlier part, more plentifully towards the end of 

 the month. Some appeared to be larger than formerly, the diameter 

 from apex to base being '024 inch, and the base being '029 inch across. 



None were captured in the mid-water net, but this probably was due to 

 the mesh of the cheese-cloth permitting them to escape. In the surface- 

 net, again, they only appeared on the last day of the month. 



The Cyplwnautes here referred to has been described by Prof. All man, 

 who obtained it in considerable abundance in the Moray Firth in 1872. 

 Johannes Midler connected it with Mitraria, Semper thought it a larval- 

 mollusk, while Schneider has the credit of tracing its development into 

 Membranipora. Very little change ensues in this type as it conies before 

 the marine zoologist in the tow-nets throughout the summer and autumn 

 and even as late as December. The transformation, therefore, probably 

 ensues to a great extent on the ground. 



A noteworthy feature was the appearance of Adinotrocha on the 5th 

 July in the bottom tow-net, and subsequently many were obtained at 

 different stages (Plate VI. figs. 1-6). 



Some were kept in the laboratory until the transformation into 

 Phoronis took place, and no marine form is more remarkable both for 

 beauty and life-history. The hooded larval form with an aperture at 

 either end (Plate VI. fig. 1) only shows a series of finely-coloured ten- 

 tacles, then an inpushing appears at one side (fig. 3), developing into a 

 long coiled tube. The animal still swims gaily about, developing rudi- 

 ments of new tentacles at the bases of the old (fig. 2). Then it 

 becomes sober, sinks to the bottom, and all at once the long internal 

 tube begins to unroll like the turning of a finger of a glove inside out 

 (fig. 4) ; the once short body now becomes elongated, and the mouth 

 and vent, instead of being at opposite poles, are now brought near each 

 other, while the stomach and alimentary canal slip into the long tube 

 (figs. 7 and 8). The hood and the central nervous system in it are 

 swallowed by the animal, and hence the puzzling nature of that part of 

 the nervous system which remains. 



Phoronis has not hitherto been observed in the Bay, though it is a well 

 known inhabitant of the Firth of Forth — since the observations of Dr 

 Strethill Wright, and the capture of Actinotroclia by Dr Cobbold. It 

 is quite possible, however, that it may also frequent certain parts of the 

 Bay. Phoronis is a common borer in limestone, and it may also affect 

 other calcareous structures, such as shells, and likewise ordinary rocks. 



Young mussels and Spinalis have now reached the surface, and often 

 occur in large numbers — along with Copepods, Evadne, Plutei, Nauplii, 

 larval Hyperiae, Cyplwnautes, and minute ova of various kinds. In these 

 collections also fragments of the ctenophoral rows of PlemrobraeMa and 

 Lesiieuria, shaped like a flattened nail (i.e. * with a head '), are very 

 abundant. Comparing this year, however, with some previous ones, 

 as, for instance, 1884, the number of pelagic mollusks was not so great, 

 especially in the upper parts of the water. 



