496 W. WOODLAND. 



Note on some Pointed Oblong Bodies present in the Wall 



OF SyNAPTA INIIiERENS. 



While searching' the internal surface of the body-wall of 

 S. inluorens for young spicules, I not infrequently en- 

 countered tlie curious bodies depicted in fig. 20. They were 

 stained a dark green, and were apparently in every case 

 enclosed each in a single cell, which was one of a cluster. 

 The surrounding cells (which often contained large vacuoles 

 not shown in the figures) did not appear to be iu any way 

 connected with the cell containing the body, and, so far as I 

 observed, only one of these bodies was contained in each 

 cluster. I did not detect any internal structure in the interior 

 of these bodies. Beyond offering the somewhat trite sugges- 

 tion that they may be parasites, I am unable to explain their 

 nature. 



Summary. 



(1) The first sign of the future spicule is the multiplication 

 of the nuclei of the dermal epithelium at one point to form a 

 syncytium. 



(2) In this syncytium a calcareous granule is deposited on 

 its internal aspect. 



(3) This granule elongates on one side either to the right 

 or to the left of the long axis of the animal to form the shaft 

 of the future anchor ; the other side of the granule persists 

 for a while as the knobbed extremity. During development 

 the knobbed extremity remains in apposition with the dermal 

 epithelium, but the opposite end comes into connection Avith 

 the subjacent fibrous layer, so that the shaft is not situated 

 tangentially in the body-wall but is inclined. The shaft, like 

 the initial granule, lies on the internal aspect of the syncytium, 

 i.e., nearly all the nuclei lie on the external side of the shaft. 



(4) When the shaft has attained its full length, and the 



