NATURAL HISTORY OF PALOLO, OR MBALOLO. 239 



minute conical teeth on its concave edge. The bundles of aetce generally consist of two 

 or three of each of these forms, the latter holding a position inferior to the former. 



3Ibalolo has been sujiposed to exhibit an alliance with Arenicola ; but the anatomical 

 characters above given refer it, very clearly, to the Nerekla;. 



DESCRIPTION OF THE PLATE. 

 Tab. XLI. 



Fig. 1. Portion of Mbalolo. Natural size. 



Fig. 2. Magnified figure of the head, with its three frontal tentacula and eyes, each of which appears to 



consist of two distinct organs closely approximated. The position of the retracted jaws is 



shown in the central dark space behind the tentacula. 

 Fig. 3. The double set of jaws, with their basal plates. 

 Fig. 4. The palatal ? erectile plates noticed in the text. 

 Fig. 5. Three of the feet, seen from below: a. setigerous tubercle; h,b,b. dorsal cirri; c,c, c. ventral 



cirri ; d. muscles which protrude the acicuh, acting through the basal stylet, e ; f. retractor 



muscles, derived from the lateral border of a longitudinal muscular band, g, running along the 



ventral surface. 

 Fig. 6. Posterior extremity of the Mbalolo, dorsal aspect ; a. terminal dorsal cirri ; b. terminal ventral 



cirri, or oval styles so called. 

 Fig. 7- Basal stylet, or that which affords support to the lateral tubercles. 

 Fig. 8. Whip-like aciculus. 

 Fig. 9. Clawed aciculus. 



