336 E. R. HOSKINS 



apex pointing toward the center of the gland. The region 

 between adjacent apices contains many small tubules which 

 have branched nearly at right angles from the primary tubules, 

 and a few small primary tubules which have developed from 

 the wall of the main lumen. The tubules in this stage branch 

 in nearly every possible maimer. Some primary tubules extend 

 unbranched to or nearly to the periphery, some divide dichoto- 

 mously near the center of the gland into secondary tubules 

 which extend unbranched to its surface. Others give off sev- 

 eral secondary tubules at right angles to their straight radial 

 course, and still others dilate suddenly near their origin and 

 branch into as many as five secondary tubules at the same place. 

 The secondary tubules branch in much the same way as those 

 of the first order, giving off tubules of the third order which, 

 in turn, branch to form tubules of the fourth order. 



In the 200 mm. Acanthias the duct of the digitiform gland 

 runs backward in the sub-mucosa for about 3.0 mm. from its 

 opening into the intestine. It then turns obliquely and pene- 

 trates the muscular layer, forming a ridge on the right dorso- 

 lateral surface of the intestine and finally extends cephalad 

 free from the intestine. The gland lies dorso-lateral to the 

 intestine. The length of the gland varies considerably, but it 

 may be over 20 mm. long. In general shape it is cylindrical, 

 but both extremities are tapering. The number of tubules 

 has increased considerably over that of the preceding stage, 

 tubules up to the sixth order being present. 



In the adult the gland has much the same shape as that 

 just described. The length has a large variability, sometimes 

 being only 2 or 3 cm., and again it may be more than 7 cm. in 

 length. The adult gland (fig. 10) contains tubules similar to 

 those described above, except that they are longer and of greater 

 diameter. Their number has increased greatly. In a single 

 transverse section of the gland over 600 tubules can be counted 

 at the periphery, and many thousands are present in the entire 

 gland. Around the central lumen of the gland are two to five 

 rows of primary and secondary tubules, extending both radially 

 and longitudinally. The next region peripheral to this and about 



