322 GASTEKOPODES. 



largest Testacea. The Nautiline exists among its spawn. Possibly the 

 Nautiline may belong to many of the Limacine species, and the univalve 

 Testacea, as well as to the Doris. 



A few facts may be stated without attempting to solve the ob- 

 scurities. 



Spots of spawn are found on marine vegetables, such as the Lami- 

 ixiriee on the shore, within low-water mark. One, from an unknown 

 parent, appeared in July, of small dimensions, and resembled a thick drop 

 of yellow colour, almost hemispherical, with a depression in the centre. 

 Possibly the true figure might have been a short bent cylinder, with the 

 ends in contact, or nearly so, thus forming a circular ring. Plate XLVI. 

 fig. 1 . Such spots consist of numerous minute white ova. When dis- 

 solving, on the 1st of August, a corresponding multitude of minute white 

 specks, proving to be Nautilines, swam actively through the water ; while 

 others remained motionless at the bottom. Fig. 2. The drop little 

 exceeded a line in diameter, and it may have been the spawn of some 

 Doris or of a testaceous animal. 



Among the varieties of appearances disclosed by the spawn of the 

 humbler animals of this tribe are the Nautilines, at rest or in motion. 

 The specks, in an ovoidal mass of spawn, somewhat more ample than that 

 from the Doris sanguifer, performed a revolution while confined within 

 the capsule, as each was confined by its own integument. The cilia were 

 quite visible while still enclosed there. Fig. 3. When released from 

 their prison by maturity, it was to display all the peculiarities of the 

 Nautiline. Fig. 4. They rose in multitudes from below, and formed a 

 scum on the surface of the water, from which they were incapable of de- 

 scending until precipitated by the vessel being shaken. Did we know the 

 sources of that which we consider spawn to have been derived, our inquiries 

 would be greatly facilitated ; we could seek for corroboration, or weigh 

 the causes of disappointment. Researches after marine products are so 

 vague and difficult, and so often unsatisfactory, that all illustrations are 

 most desirable. The two figures, 3 and 4, represent Nautilines from an 

 ovoidal mass of spawn, from an unknown parent. In the former they 

 are still confined, each within its own integument ; in the latter they are 



