of the Fishery Board for Scotland. 



271 



them, and yet comparatively little indication of their presence in such 

 numbers was given by any other net than that just indicated. These 

 little fishes form the prey of many invertebrate forms, even so small a 

 medusoid as Lizzia boldly seizing on the head of a sickly specimen and 

 tenaciously clinging to it ; and it is not uncommon to find one inside 

 the manubrium of Circe. Higher types, such as young fishes, feed on 

 them greedily ; indeed, their minute size, activity, and transparency alone 

 protect them. The greenish silvery sheen of their eyes, however, must 

 often prove disastrous in the case of the larger fishes, which almost uni- 

 versally pursue them. A very great amount of valuable fish-food is thus 

 provided by the superabundance of these larval Clupeoids. 



May. 



An algoid structure of some interest appears in the Bay in April, during 

 this month, and the next, viz., great numbers of small gelatinous bodies, 

 ovoid, dumb-bell shaped, or somewhat cylindrical in outline (Plate III. 

 figs. 1 to 4). Their long diameter varies from 1 to 2 mm., and thus they are 

 much smaller than examples of the Hadiolarians, e.g., Collozoum inerme. 

 When removed from the mid-water net they float somewhat heavily near 

 the bottom of the glass vessels, though it is probable that their range in 

 the open sea varies in depth according to circumstances. Moreover, in 

 June, they specially abounded in the estuary of the Eden, and this distri- 

 bution perhaps may give a clue to their origin. They presented a hyaline 

 gelatinous matrix (Plate V. fig. la), in which were studded small 

 greenish-yellow cells containing nuclei, and many of which, from their 

 constricted aspect, appeared to be in a state of division. Occasionally 

 somewhat large, round nucleated cells occurred amongst the others. In 

 many, again, minute fusiform spicular bodies, or acicular bodies like 

 spicules (Plate V. fig. 2), were sparsely scattered throughout the 

 protoplasm, after the manner of certain Radiolarians, e.g., the Sphcerozoum 

 neapolitamim, as figured by Brandt. After preservation in spirit, the 

 latter (spicules) became finely granular, and were rendered invisible by 

 mounting in calcium chloride. 



The vast abundance of these algoid structures in the Bay could not but 

 have an important influence on the fauna, and this was especially seen in 

 regard to the Appendicularians, and perhaps in Tomopteris and other forms. 



Rhizosolenia formed a conspicuous feature of the water during May, 

 and it not only occurred in, but beyond the limits, penetrating, 

 moreover, all the harbours and creeks connected with it — so as to give 

 occasionally a greenish tint to the water — on the surface of which the dull 

 greenish sparkling structures were visible to the naked eye. The vast 

 abundance of this algoid form sometimes interfered with the working of 

 the nets, the pores of which were plugged, thus retaining the water and 

 masses of Appendicularians and their houses, so that the boat was anchored 

 or the sail-ropes broken. The distribution of Rhizosolenia varied ; thus on 

 the 10th May, it was chiefly at the upper region, within two fathoms of 

 the surface, while the lower parts were occupied by Appendicularians ; 

 while on other occasions it occurred towards the bottom or throughout the 

 entire depth. 



The fishermen at this time considered the water extremely muddy, 

 probably from disturbance of the bottom by the easterly wind, and did 

 not appear to connect the profusion of Rhizosolenio3 with the obscurity. 

 They also imagined that under these circumstances the fishes did not see 

 the bait, while others were of opinion that they had left the Bay. The 

 latter, however, can hardly be correct, since many delicate young gadoids 



