428 THE CORYNACTIS. 



much diversity in the manner of the projection of the 

 thread. In many cases, especially in such capsules 

 as were found loose in the enveloping mucus, (libe- 

 rated probably in the act of detaching the fragment 

 for examination,) the thread was found already shot 

 to its utmost, when presented to the microscope, 

 before pressure was applied with the compressorium. 

 Many under pressure projected it in a moment, and I 

 invariably found that the imbricate structure could 

 be made out only in such threads as were thus per- 

 fectly and suddenly expelled. 



But it was quite as common for the thread to shoot 

 out partially, and by starts, a coil or two at a time 

 emerging ; and in this case, the projected part appear- 

 ed thin and shrivelled, with no defined marks, nor 

 even a distinct diameter. I think the cause of this 

 imperfect transmission was always some obstruction 

 lying in the way of the tip of the thread, sometimes 

 overcome, but often presenting an insuperable barrier, 

 when the capsule would remain half empty, the an- 

 terior portion of the coil having disappeared, but the 

 posterior part remaining unchanged. 



A curious proof of the projectile force employed 

 was by accident presented to me. The tip of a thread 

 in the act of emission came into contact with a cap- 

 sule already emptied. It was stayed for an instant : 

 but the crystalline wall of the capsule was driven 

 inward in an indentation, and presently it yielded, 

 and the thread forced its way in, shooting all round 

 the interior of the oval cavity. 



These capsules, and even their projected threads, 

 are distinctly visible with a common triple pocket-lens. 



