Notes on the British Species of Lepadogaster. 167 



(8.) the posterior margin of the operculum instead of being 

 rounded is distinctly angular, and is continued into a spinous 

 process ; (9.) the paired latero- ventral ocelli appear to be 

 invariably absent ; (10.) the general body colour is usually 

 a dirty greenish-brown without any very prominent mark- 

 ings, but dredged specimens generally have a reddish hue, 

 which becomes paler towards the ventral surface. It will 

 be seen that many of the features which distinguish this 

 species from the preceding are characters which it shares 

 in common with L. Decandolli. Such are the condition of 

 the skin, the rigidity of the fins, the shape of the posterior 

 margin of the operculum, etc. This is by far the most 

 abundant species on the West Coast of Scotland, and appears 

 to be generally distributed. I have obtained it between 

 tide-marks in Eothesay Bay and in Lochfyne. I have also 

 obtained it by means of the dredge in the Firth of Lome 

 (10 to 15 fathoms), and as far north as Loch Boisdale (3 to 

 4 fathoms). Saville Kent thinks his form is a truly littoral 

 species and that in this respect it differs from L. himacidatus. 

 I cannot say whether the species just described is the same 

 as that referred to by Saville Kent, but my observation 

 tends to show that L. microceplialus usually frequents the 

 off-shore waters. In certain districts large numbers of this 

 species come inshore in the early summer, apparently to 

 spawn, and they may then be taken in numbers between 

 tide-marks, but it is equally certain that for nine or ten 

 months out of the twelve, in the same localities, not a single 

 specimen is to be found. 



Develop77ient of the Vertical Fins. 



In September 1887 I obtained a few larval forms of 

 L. microcephalus in Loch Boisdale, together with two or three 

 adult specimens. They vary from 7 to 9 mm. in length, and 

 show an interesting stage in the development of the vertical 

 fins. The continuous embryonal fin still exists in larva3 of 

 7 mm. (c/. PI. YIL, Fig. 1). In larv« of 9 mm. (PL VII., 

 Fig. 2) the embryonal fin is divided up into dorsal, caudal, 

 and anal. It will be seen from the figure that the part of 

 the embryonal fin which is later absorbed, remains at this 



