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the cells, vrhile at other places there is no apparent regularity 

 In their arrangement. In ^XE* 6 a, the short cells with large 

 nuclei are seen on either side of the slit-like openings (o.) 

 into the groups of gland cells. The ciliated grooves (v.c.g.), 

 at the point v/here this section is cut, are still some distance 

 apart on the floor of the pharynx, and are not noticeably changed 

 from their condition in the preceding stage. They are separated 

 by one large and two small folds in the floor of the pharynx, 

 v/hioh seems, at this point, to be very irregular in outline, 

 probably caused partly by shrinkage at fixation. They are very 

 deep and narrow and seem filled completely by their cilia. 



The connective tissue covering (c.t.) of the thyroid, 

 spoken of in connection with the outv^ard appearance of the thyroic^ 

 is seen, in section, to form a thick layer entirely around the 

 gland, and to form the central mass of the median lamella (m.l.). 

 It also forms a thick coating around each branch of the large 

 artery which Dohrn calls the Pseudobranohlal artery (Spritz- 

 locharterie) (art.). The large, and now nearly enclosed space 

 (i.v.), formed by what v/as called the "lateral invagination", 

 is more or less completely filled by a sort of reticulated tissue 

 with scattered nuclei. This reticulated tissue also fills the 

 space betv/een the floor of the pharynx and the thyroid. rumerous 

 small blood vessels are found imbedded in it, both in that v/hich 

 fills the lateral invagination and in that which lies between 

 the gland and the pharynx. This tissue is represented only in 



