330 E. R. HOSKINS 



The terminology of the digitiform gland has been much con- 

 fused. Alexander Monroe secundus (1785) seems to have been the 

 first author to give a name to the gland in question. He referred 

 to it as the appendix digitiformis, but did not describe it. The 

 structure has also been termed the bursa cloacae (Retzius '19), 

 the Darmanhang (Carus '34 and Gegenbaur '78), the caecal 

 appendage (Owen '46), the superanal gland (Blanchard '82) 

 and the anal gland (Crawford '99). Mention of the structure 

 is found in a large number of early works on comparative anat- 

 omy, as for example, Cuvier (1810), Blainville (1811), Home 

 (1814), Rathke ('27), Leydig ('52), Hyrtl ('58), Stannius ('54), 

 Dumeril ('65), and others. It has been seen in all selachians. 

 Glandular elements which seem to resemble the digitiform 

 gland are found in the wall of the intestine of Chimaera (Mazza 

 et Perrugia '94, Morgera '10). 



Blanchard ('78 a, '78 b) gave the first account of the develop- 

 ment of the digitiform gland. He found the gland in an Acan- 

 thias embryo 23 mm. in length, developing from a groove on 

 the left dorsal intestinal wall. The 'glandules' are embedded 

 in connective tissue which penetrates to its internal surface. 

 Each 'glandule' is surrounded at its mouth by smooth muscle. 

 In Blanchard's figures 7 and 8 ('78 a), the main lumen of the 

 gland is pictured as fined with connective tissue for which he 

 seems to have mistaken the stratified epithelium. Blanchard's 

 statement that the gland develops on the left side of the intes- 

 tine is incorrect, as its origin is always from the right side. 



Sanfelice ('89 a, '89 b) noted the digitiform gland in Pristiurus 

 and Torpedo embryos, 15 mm. in length. In embryos 19 to 

 20 mm. long the gland had lengthened, the epithelial cells were 

 cylindrical with regular nuclei. The last stage described (30 

 mm.) showed many outpouchings from the central lumen. 



Hoffman ('93) reported that in Acanthias and Mustelus em- 

 bryos up to 26 mm. in length no blood vessels exist in the digi- 

 tiform gland. They were found in earlier stages in the pres- 

 ent investigation. 



Scammon ('11) stated that the digitiform gland of Acanthias 

 appears first in embryos of 18 mm. in length, as a solid bud on 



