576 W. BLAXLAND BENHAM. 



blance to the "thread-containing cells" of Vermiculus, 

 described by Goodrich, differ in a few details. 



The relative number varies somewhat in different worms, 

 and the appearance of the cell and degree of development of 

 the thread within are subject to considerable variation ; 

 though whether this is due to individual or other causes I 

 am as yet uncertain. 



When a drop of the coelomic fluid is examined under a low 

 power there are seen, amongst the refringent cells just 

 described, a few clear, almost transparent, and somewhat 

 yellowish cells (fig. 1, d.), much larger, as a rule, than the 

 granular amoebocytes, and sometimes nearly as large as the 

 eleocytes. If this fluid has been mounted without any 

 precautions, but merely taken from the coelom, this clear cell 

 will show, either immediately or after a short time, a circular 

 vacuole within — or sometimes more than one vacuole, — which 

 may be circular, or oval, or irregular. The margin of the 

 vacuoles is clear and slightly more refringent than the cyto- 

 plasm, and has the appearance of a ring, which becomes 

 more evident after the death of the cell. This "ring," Avhen 

 carefully examined, appears to be made up of a coiled fine 

 thread, which is faintly yellow, but prolonged study modified 

 this conception of a "coiled thread." Before discussing the 

 interpretation to be put upon this cell-product, it will be 

 convenient to describe an average form and some less usual 

 types. 



Usually, the linocyte (fig. 9) is spherical, of about half 

 the size of an eleocyte. The cytoplasm is finely but regu- 

 larly granulated, and forms a superficial envelope to the con- 

 tents, and it is bounded externally by a distinct envelope. 

 The nucleus is oval, aud lies iu the peripheral cytoplasmic 

 coat, which is thicker in its neighbourhood than elsewhere. 

 The greater part of the cell is occupied by a slightly 

 refringent, clear, faintly yellowish inclusion — which for 

 convenience may be termed a "coiled thread," for even in 

 the most carefully mounted preparations the refringent 

 outline of the inclusion, be it oval or circular, soon shows 



