Dr James M'Bain on the Development of Fish Spawn. 373 



the larva of Notodonta or Amphipyra, and the rest of the 

 body is uniformly cylindrical, the fifth and the sixth seg- 

 ments bearing a pair of large eye-like spots, somewhat like 

 those of the larva of Chcerocampa. The position, when at 

 rest, is most remarkable, the body resting on the three pairs 

 of perfect ventral claspers alone, with the anterior segments 

 elevated and incurved, after the manner of the Sphinges, 

 and some of the Geometrce, while the posterior segments are 

 elevated in the air after the fashion of the genus Notodonta. 



The drawings are on their way to London, I believe, to 

 be placed in the hands of Mr Moore ; so that their details 

 may be expected to be embodied in the forthcoming volumes 

 of the Descriptive Catalogue of the Insects in the Museum 

 of the East India Company. 



II. Notice of the Development of Fish Spawn from the Firth of Forth. 

 By James M ; Bain, M.D., R.N. 



On Tuesday the 11th instant, when examining fish spawn 

 under the microscope, I observed a free and complete rota- 

 tion of the embryo in the ovum, which rotatory movement 

 was repeated at short intervals. The spawn had been 

 dredged up four days previously in 14J fathoms water, half 

 a mile to the westward of the Isle of May ; and in all the 

 ova which had a clear transparent appearance the same rota- 

 tory motion was observed. The following day, on making 

 similar observations, the embryos were still found alive, 

 and rotating freely in the ovum ; and fresh spawn dredged 

 up at the same place exhibited similar activity of embryonic 

 movement. The spawn in which this vital action was seen 

 is said by the fishermen to be the herring spawn ; and to as- 

 certain, if possible, to what species it really belongs, I pre- 

 served small portions of the spawn in sea-water. On the 

 18th instant, I was pleased to see a numerous brood spon- 

 taneously extruded from the ova, swimming freely about in 

 the vessels in which they had been placed. 



The ova were about of an inch in diameter, and the 

 young fry, when first extruded, measured two to three lines 

 in length. A few of the young fish are now, eight days 



