302 Zoological Society. 



a ring formed of its seinigelatinous coats) to a leaf of Zostera marina. 

 They were of an elongated oval shape, about 1 inch in length and 

 nVths in breadth ; colour black, shining; consistence soft. Tunics 

 of the ovum very numerous, of various thickness, arranged concen- 

 trically. When these tunics were removed in succession until the 

 ovum became transparent, I saw distinctly the contained foetus and 

 its yelk within the inner coat. 1 could see it move and respire. 

 When the egg was gently pressed, it moved briskly. I succeeded in 

 getting the inner membrane with the contained foetus out of the 

 egg entire. I kept one in this state in sea-water for many hours, 

 at the end of which time no change had taken place. Others I 

 opened, and let out the foetus ; at first preserving it in its own fluid. 

 Its only evident motion was that of respiration performed with more 

 or less activity, according to the degree of disturbance given to it. 

 When at rest, the respirations were thirty two per minute. The sac 

 was dilated, and the funnel raised as in the adult ; and from the 

 transparency of the mantle, I could see plainly the motions of the 

 lateral valves. The surface was marked with several spots ; pro- 

 portionally, not so numerous as in the adult. These seemed to me 

 to become larger after the removal from the egg j but 1 saw no con- 

 traction and dilatation similar to what occurs in the adult. The 

 yelk at first adhered to the front of the body, being placed between 

 the arms ; but I could not see how it was attached. In a short time 

 it dropped off. It seemed to consist of a very thin membrane, in- 

 closing a homogeneous transparent jelly. The lateral fin was broad, 

 and, when the animal moved, had much wavy motion. When 

 touched, before the yelk separated, the sac was contracted, raised, 

 and a sharp expiration took place. The same, after separation of 

 the yelk, was sufficient to make the animal move backwards a short 

 distance. When salt-water was mixed with the fluid in which the 

 foetus floated, the animal, at first, appeared uneasy, drew its mantle 

 over its eyes, and breathed quickly. This agitation, however, soon 

 subsided, and there seemed to be additional vigour imparted. 

 Viewed ventrally, the ink bag's silvery coats were seen shining 

 through the mantle; and when the animal was touched, it twice or 

 thrice ejected minute streams of ink. Whole length of the foetus 

 -,Vths of an inch. The eyes were very large proportionally. The 

 suckers on the arms appeared only as minute tubercles. The shape 

 of the yelk was nearly spherical ; diameter about -rVths of an 

 inch. 



" Nov. 12. — The fcetus taken out of its egg on the 10th instant 

 was, on the same evening, put into salt water, which happened to 

 be muddy; it continued to respire, and appeared well all the even- 

 ing ; but afterwards its sac contracted so as to allow the lateral 

 valves to be seen outside, and it was languid : next morning it was 

 dead. Today I dissected it. The shell was found loosely imbedded 

 in the mantle. It was Wths of an inch in length ; white; in shape 

 ovate; thickest at the narrow end, where it was almost opaque; 

 composed of five concentric layers; outermost very thin, translu- 

 cent, spotless ; others marked with variously shaped spots ; near the 



