THE ANATOMY OF AN AUSTRALIAN LAND PLANARIAN. 73 
In sections of an unstained animal certain irregular masses lying in the zone of 
mucous glands, and probably themselves mucous glands, were observed to have a blue 
colour. JI am unable to say whether or not this colouration is constant for the 
mucous glands, but I shall show presently that the blue pigment which forms so 
conspicuous a feature of the living animal is lodged principally in the rod-like bodies. 
G.—The Rod-like Bodies (Rhabdites ).—The nature of these remarkable organs has 
given rise to a good deal of discussion, and no very satisfactory conclusion has as yet 
been arrived at concerning them. 
Moseley (6) describes the existence of the rod-like bodies in the epidermis and 
their origin in parent cells ‘“‘ beneath the external longitudinal muscle layer.” 
According to him these parent cells are, in spirit specimens, of an elongated oval 
form, with the upper extremity drawn out into a point or long filament; when cut 
transversely they are seen to be divided into two or three compartments, and they 
have a very stout, horny-looking cell-wall. ‘‘In vertical sections they are usually seen 
to contain more than one rod-like body, often three, in apparently different stages of 
development. The cells have usually a nucleus-like body at their inferior 
extremity.’’ Moseley concludes that these peculiar structures are homologous in all 
Planarians, but he wisely leaves the much vexed question as to their relation to the 
thread-cells of the Celenterata alone. 
In the main this account agrees with the state of things in Geoplana spencerz, but 
IT must call in question the statement that the parent cells are divided into two or 
three compartments and have a very stout, horny-loooking cell-wall. These 
appearances are, in all probability, due to the action of re-agents. 
Hallez (5) also describes the formation of rod-like bodies within parent cells, but 
his views concerning the position and origin of the latter are certainly incorrect if 
applied to land Planarians. I need not quote them here, but refer the student to 
his monograph. 
Von Kennel’s account (8) of the rod-like bodies in the German land Planarians 
requires more consideration, because his observations were made upon forms closely 
allied to those studied by Moseley and myself. He describes them as existing in the 
epidermis of the dorsal surface, between the epidermic cells, and in very large 
numbers. This also holds good for Geoplana spenceri. He states, however, that in 
Rhynchodemus there exist two kinds of rod-like bodies—(1) larger, egg-shaped, 
elliptical, or spindle-shaped bodies; (2) smaller, thread-like, sharp at both ends, 
usually curved at one or both ends so as often to form a circle, always of quite 
