1 90 



THE ASCWIANS. 



Fig- 97- Hypophysis of Phallusia 

 mentula, prepared out and seen from the 

 inside. (After JULIN.) 



g. Subneural gland, above which may 

 be seen the outline of the ganglion and its 

 nerves, d. Duct of the subneural gland. 

 t. Dorsal tubercle, the opening of the 

 hypophysis into the branchial sac. The 

 actual opening is indicated in black. 

 pc. Peripharyngeal groove. ep. Epi- 

 branchial groove, d.l. Dorsal lamina, 

 slightly displaced, to show the duct of the 

 subneural gland above it. 



N.B. In this species, the atrial and 

 buccal siphons are widely separated, and 

 the duct of the subneural gland is very long. 



The dorsal tubercle was 

 discovered by the celebrated 

 SAVIGNY in 1816, and was 

 for a long time supposed to 

 be an independent sense- 

 organ of an olfactory nature. 

 The subneural gland was 

 detected not as a gland, but 

 as an enigmatical structure 

 lying below the brain by 

 the English naturalist HAN- 

 COCK in 1868. Its glandular 

 character was demonstrated 

 by NASSONOFF and Ussow 

 in 1874-75, the last-named 

 author showing its connex- 

 ion by means of the duct 

 with the dorsal tubercle. In 

 1 88 1 JULIN produced an 

 admirable memoir on the 

 subneural gland and its duct, 

 and strongly urged its ho- 

 mology with the pituitary 

 body or hypophysis cerebri 

 of the higher Vertebrates. 

 The same suggestion was 

 made in a more tentative 

 form in the same year by 

 BALFOUR. We shall have 

 to consider this question 

 later. Suffice it to say at 

 present that Julin's sugges- 

 tion has been accepted to 



