SERTULARINA. 



119 



Tlie embryo, however, of so few species of Sertularians has been yet seen, that 

 general deductions should be hesitatingly received until a wider series of facts has 

 been recorded. To contribute to this desirable end, I gladly avail myself of Mr, 

 Peach's permission to publish his observations on Laomedca dichotoma and Campa- 

 nularia volubilis. On the 19th of February, 1842, Mr. Peach placed a specimen of 

 this Laomedea in a large glass filled with sea-water. On the 22nd the water ap- 

 peared muddy, and this appearance was occasioned by myriads of moving embryos. 

 "■ I took," says Mr. Peach, " a small quantity of the water, and placed it under the 

 microscope, when thousands of the objects figured (Fig. 25) were sporting about in 

 all directions, moving at a rapid rate by the ciliary appendages on their rnn. All at 

 once they would withdraw their cilia and 



the handle-like appendage on the back. Fig. 25. 



and become a mere speck ; and after rest- 

 ing a short time, they would again throw 

 out their cilia and appendage, and round 

 they went waltzing with each other. It 

 was perfectly astonishing, in this crowded 

 assembly, to find that they very seldom 

 came into collision, and if so, how soon 

 matters were again accommodated. They 

 continued active up to the 2nd of March, 

 when I lost them as if by magic. I fan- 

 cied they might be the young of worms, therefore I took the specimen of Laomedea, 

 washed it, took fresh sea-water and filtered it through three or four folds of fine 

 linen, and placed the specimen in this : the next morning I had a still more innu- 

 merable host of these delightful things. They are represented in various positions, 

 and when in the water they reminded me of thousands of parachutes thrown from a 

 balloon, descending in various states of expansion." 



"On the 2nd of March, 1842, my Campanularia which I got on the 19th ult. 

 also sent forth gemmules of the shape of 

 fig. 26. I compared them to wire roasting- 

 jacks, which have lions' heads made of 

 lead to hold the wires together : these 

 jacks are suspended by a string. They 

 had no cilia, and moved by jerks, closing 

 and opening ; they had a film-like ap- 

 pendage attached to the ribs : in fact, 

 the others appear film-like, but spotted. 



— I took the same precaution with these as the others, filtering the water, &c. &c. 

 These lived only five days." 



Fig. 26. 



