780 GLASS XIII. 
Placobranchus V. Hass. 
Comp. VAN Hassexr in Bullet. univ. DE Frrussac, 1824, Oct. p. 240. 
Scarcely distinct from the preceding genus, with which it is conjoined by 
Lovén. 
B. Branchie external at the sides of back, numerous, tentaculiform. 
+ Vent posterior, mm the middle of back. 
Janus VERANY, Antiopa ALD. and HAnc. 
Comp. QUATREFAGES Ann. des Sc. nat. 3e Série, XI. 1849, pp. 76—go, 
Pl. 3, 4. Sp. Janus Spinole, Holidia cristata DELLE CHIAJE. See also 
Ann. of Nat. Hist. sec. Series, I. p. 190. 
Proctonotus (Venilia previously) ALD. and HaAnc. 
Comp. ALDER and Hancock Annals of Nat. Hist. 13, 1844, pp. 161— 
164 and p. 407, Pl. 2. Here also is to be referred as it seems genus Zephy- 
rina QUATREF. [According to ALDER and HANcocK the two differ in that 
four linear tentacles are seen from above in Zephyrina, whilst in Proctonotus 
the two larger are dorsal and the smaller arranged at the sides of the velum 
which covers the head. Monograph. No. v. Procton.] 
tt Vent lateral, to the right. 
Alderia ALLMAN. 
Comp. ALLMAN Ann. of Nat. Hist. Vol. 17, 1846, pp. 1—5. 
Stiliger HHRENB. 
Pterochilus ALDER and HANc. 
MHolidia Cuv. (4éolis or Holis auctor.). Tentacles four. 
Angles of foot lateral, the anterior mostly produced. Branchie 
placed at the sides of back, numerous, tentaculiform, emitting 
stinging filaments at the perforate apex. 
Sp. Molidia papillosa, Limax papillosus L., Syst. nat., BAasteR Natuurk. 
Uitsp. 1. Tab. X. fig. 1, bl. 93, 94, Ann. of Nat. Hist. xv. Pl. 1. fig. 1, 
ALDER and Hane. Monog. Pt. vi. Fam. 3, Pl. 9; this little animal.attains 
a length of 2 inches. Comp. Hancock and D. EMBLETON on the Anatomy 
of Holis, Ann, of Nat. History, xv. 1845, pp. I—10, pp. 77—88, sec. 
Series, 1. 1848, pp. 88—1os, Frey u. LEvcKAR? Beitr. z. Kenntniss wirbello- 
ser Thiere, 1847, 8. 54—64. The coecal branches of the intestinal canal 
are extended in the Holide into the branchial appendages. These appen- 
dages have at the point a small vesicle, from whence filaments resembling 
spermatozoa (nettle-threads, see above, p. 99) come to view. Ann. of Nat. 
Hist. xv. Pl. tv. Pl. v. figs. 1—11. 
In the neighbourhood of Molidia some genera or sub-genera of later 
authors may be placed, all of which cannot be noticed here. Lolidina 
