42 BRACHYPODELLA. 



and Bcrcndtia. The cerebro-pedal and cerebro-pleural con- 

 nectives are long. The pedal, pleural, visceral and parietal 

 ganglia do not form a compact suboesophageal mass, but a 

 large open ring, chiefly by reason of the separation of the 

 pleural and pedal ganglia by rather long connectives. The 

 cerebral ganglia are not noticeably subdivided. They are 

 united by a broad commissure. The bases of the optical 

 nerves are not noticeably enlarged (pi. 14, fig. 1: c, cerebral 

 ganglia; par., parietal; ped., pedal; pi., pleural; v, visceral 

 ganglia; o, base of the optic nerve). 



The buccal mass or pharynx is of the short, oblong form 

 usual in this and allied families, but the radular sheath is 

 enormously lengthened, at least half as long as the shell in 

 B. chemnitziana and B. agnesiana (pi. 14, fig. 2, ph, pharynx; 

 r, radular sheath ; /, foot) ; and it projects free in the visceral 

 cavity, the forward part being thrown into longitudinal folds. 

 The distal end is noticeably dilated. The radula is corres- 

 pondingly long and narrow. The special modifications of the 

 teeth are discussed under the several subgeneric heads. 



Compared with Urocoptis (see vol. xv, pi. 27, fig. 44), it 

 will be seen that Bracliypodella presents various differences 

 in the soft anatomy. The pharynx and salivary glands are 

 similar, but the radular sheath in Bracliypodella stretches its 

 enormous length far into the visceral cavity. The muscles 

 are not very unlike, but they are united further at the prox- 

 imal end in Bracliypodella, and the left ocular retractor in- 

 serts upon the vas deferens and vagina, a normal penis- 

 retractor being present. In Urocoptis ~brcvis a condition fur- 

 ther advanced has been attained, the insertion of the ocular 

 band having moved downward to the apex of the penis itself, 

 where it functions as a penial retractor, the true penis- 

 retractor being superseded and lost. These differences are 

 such as would be expected in the two widely differentiated 

 genera of the same subfamily. Some other divergencies are 

 adaptive, dependent upon the viviparity of Bracliypodella 

 chemnitziana; and upon the sinistrality of B. chemnitziana 

 and ayncsiana, causing the morphologically right side and 

 organs of these forms to be on the left side. Unfortunately, 



